# Troubleshooting Unity Connection voicemail-to-email and notifications Canonical: https://warmtransfer.net/knowledge/unity-connection-notification-troubleshooting Last verified: 2026-10-02 Unity Connection has 8 default notification devices that cannot be deleted: Pager, Work Phone, Home Phone, Mobile Phone, SMTP, HTML, HTML Missed Call and HTML Scheduled Summary[^4]. Cisco's troubleshooting guidance covers several distinct problems: notification devices that do not work at all, slow or intermittent notification, messages that cannot be relayed, and single inbox messages that do not synchronise[^25][^30][^35][^34][^57]. ## How notification devices behave Cisco says not to change the display names of the 8 default notification devices[^4]. A notification device triggers only for the message types selected in its Notification Rule Events[^26]. For example, a device set to trigger on urgent voice messages only does not fire for regular voice messages[^26]. Notification devices added in Unity Connection Administration are active at all hours by default[^2]. Users may therefore be notified at unexpected times until a schedule is set in the Cisco PCA[^2]. Notification device schedules are changed in the Cisco Personal Communications Assistant, not in Unity Connection Administration[^35]. Administration reaches the schedule through the Edit Notification Device Details link on the device page[^35]. Unity Connection does not detect notification failure for SMTP devices[^39]. For that reason, Cisco says not to configure SMTP devices in a chained message notification except as the last device[^39]. The On Notification Failure > Send To failover option covers missed phone and pager notification attempts, but it is not available for SMTP notification devices[^6]. A maximum of 3 custom HTML-type notification devices can be created per user through the Bulk Administration Tool[^15]. Voice messages can be attached to HTML notifications only when the administrator enables "Allow voice mail as attachments to HTML notifications"[^14]. The default maximum attachment size is 2048 KB, and secure or private messages cannot be sent as attachments[^14]. ## Diagnosing notification devices **Device not working at all.** Check two things first: that the device's Enabled check box is selected, and that its notification schedule is active at the time notification should occur[^25]. Then confirm that the Notification Rule Events include the message type the user expects to trigger on[^26]. **Intermittent notification.** An inactive schedule is the documented cause of intermittent notification[^35]. **Slow notification for many users.** Cisco says to run the Port Activity Report from Serviceability > Tools > Reports[^30]. If notification port usage exceeds 70 percent at peak, configure additional ports for message notification[^30]. If usage is below 70 percent, contact Cisco TAC[^30]. **SMS notification failures.** Cisco directs administrators to verify the provider settings under System Settings > Advanced > SMPP Providers against the provider's specification[^38]. Cisco also directs administrators to enable the SMS Device micro trace at level 30[^38]. The trace errors mean the following[^37]: - "SmppConnect failed": Unity Connection could not connect to the SMPP provider[^37]. - "SmppBindTransmitter failed": authentication with the provider failed[^37]. - "SmppSubmitSm failed": message submission to the provider failed[^37]. ## Diagnosing SMTP and HTML notification **SMTP notifications failing for multiple users.** Cisco says to confirm all of the following[^40]: - A smart host is set at System Settings > SMTP Configuration > Smart Host[^40]. - The smart host accepts messages from the Unity Connection server[^40]. - The Connection SMTP Server service is running[^40]. - The Connection Notifier service is running[^40]. **HTML notifications not arriving.** Cisco's checklist is[^17]: - The HTML notification device is enabled on the user[^17]. - The device's email address is present and correct[^17]. - An SMTP smart host is configured[^17]. - The Connection SMTP Server and Connection Notifier services are running[^17]. The HTML notifications troubleshooting chapter also says to confirm that the Unity Connection Notifier service is up and running[^16]. **Securing the connection to the smart host.** Secure (STARTTLS) and authenticated SMTP client communication from Unity Connection to a smart host is supported from Unity Connection 14SU2 onward[^42]. To turn it on, the administrator does the following on System Settings > SMTP Configuration > Smart Host[^43]: 1. Select Enable Secure Client[^43]. 2. Set the secure Host Port[^43]. 3. Optionally enable Use Authentication and enter the smart host username and password[^43]. 4. Save and restart services[^43]. Per the CUPI SMTP client API, the IsClientSecure setting controls the connection[^41]: - Unchecked: Unity Connection connects to the smart host on port 25 without STARTTLS[^41]. - Checked: Unity Connection connects on port 587 using STARTTLS[^41]. ## Diagnosing message relay If Unity Connection cannot relay a message to the correct address, Cisco says to make sure the smart host entered on the server is correct and reachable[^34]. Cisco also says to review the message relay logs[^34]. **Delivery-loop protection.** Unity Connection will not relay a message when the relay address matches a user's SMTP proxy address, to avoid delivery loops[^32]. Cisco recommends using the precise address of the destination mailbox, for example alias@mailserver, as the relay address[^32]. **Misconfigured proxy addresses.** Cisco technote 117705 attributes relay failures with the Relay or Accept & Relay actions to misconfigured SMTP proxy addresses[^31]. In that case the SMTP log shows "Pickup Folder Monitor: No New Messages found"[^31]. The fix is a correct SMTP proxy address on each user or VPIM contact[^31]. **Private and secure messages.** Unity Connection sends a non-delivery receipt to the sender when it cannot relay a message because the message is marked private or secure[^33]. Relaying such messages requires the separate checkboxes under System Settings > Advanced > Messaging[^33]. **Malformed messages.** A malformed message goes into the MTA bad mail folder (UmssMtaBadMail) rather than to the Undeliverable Messages list[^3]. Unity Connection checks that folder nightly and logs an error when it finds messages there[^3]. ## Diagnosing single inbox synchronisation **Single inbox not working for any user.** If single inbox fails for every user with Exchange or Office 365, Cisco says to confirm in Cisco Unity Connection Serviceability that the Connection Mailbox Sync service (Critical Services) is Started[^57]. For Gmail (Google Workspace) single inbox failing for all users, the service to check in Critical Services is Connection Google Workspace Sync[^56]. **Using the Test button.** Unity Connection provides a Test button in two places: on the unified messaging service (Unified Messaging > Unified Messaging Services) and on each user's unified messaging account[^58]. The Task Execution Results page identifies configuration problems[^58]. **401 errors.** A 401 error in unified messaging testing can be caused by a wrong password, a wrong username, or a wrongly formatted username on the unified messaging services account[^54]. It can also mean the authentication mode configured in Unity Connection does not match Exchange[^54]. **403 errors.** A 403 error indicates that Exchange or Office 365 requires SSL but the public CA certificates that signed the Exchange server certificates have not been uploaded to Unity Connection[^55]. **Office 365 OAuth events in CiscoSysLog.** For Office 365 OAuth, the CiscoSysLog event EvtMbxOAuthAccessTokenDBSaveSuccess confirms a successful token refresh and is expected roughly every 50 minutes[^29]. The other documented events are: - EvtMbxOAuthAccessTokenRefreshThreadFailed means the Connection Mailbox Sync service should be restarted[^29]. - EvtMbxOAuthHttpStatusCode 401 means the Application ID, Client ID and Client Secret values on the unified messaging service should be verified[^28]. - EvtMbxOAuthHttpStatusCode 0 points to the Proxy Server and Active Directory DNS Domain Name settings on the unified messaging service[^27]. **Service account synchronised from on-premises Active Directory.** Single inbox with Office 365 may not work when the Unity Connection service account was created in on-premises Active Directory and synchronised to Office 365, because Unity Connection cannot handle ADFS[^1]. Cisco's fix is to create the account locally in Office 365[^1]. **Exchange synchronisation delays.** Cisco says to verify that the Connection Jetty service is started and that the Exchange server can reach Unity Connection on TCP port 7080[^48]. Cisco recommends CsMbxSync micro trace level 19 to watch outstanding requests, which should not exceed 999[^24]. **Resetting accounts and services.** Resetting a unified messaging service delays synchronisation for every user associated with that service while Unity Connection resynchronises[^59]. Try a per-user account reset first[^59]. **What is in scope for synchronisation.** In 15SU4 and later, single inbox message synchronisation covers only the default Outlook folders Inbox, Junk Email and Deleted Items[^11]. Voicemails in user-created subfolders are outside the supported scope and are treated as deleted[^11]. With single inbox, secure messages are stored only on the Unity Connection server[^36]. Only a decoy message explaining secure messages is replicated to Exchange[^36]. ## Exchange Online EWS deprecation and Graph API **Affected releases.** Field Notice FN74365 (revision 1.0, 15 April 2026) lists the following as affected by the Exchange Online EWS deprecation for unified messaging with Microsoft 365[^7]: - Unity Connection 14, all releases through 14SU6[^7]. - Unity Connection 15 releases earlier than 15SU4[^7]. **Symptom.** Per FN74365, affected systems fail to synchronise voicemail with Exchange Online[^9]. The admin console reports "Failed to Connect to Microsoft endpoint using https://outlook.office365.com"[^9]. **Remedy and deadlines.** FN74365's remedy is to upgrade Unity Connection to 15SU4 or later, which uses Microsoft Graph API for Office 365[^8]. FN74365 set 1 October 2026 as the upgrade deadline, the date from which Microsoft said it would block EWS requests from non-Microsoft apps[^8]. Microsoft's EWS deprecation timeline says EWS starts to be disabled globally for all Exchange Online organizations in October 2026[^5]. The same timeline says EWS is fully disabled in April 2027[^5]. **On-premises Exchange is not affected.** FN74365 states that the EWS deprecation applies only to Exchange Online and that there is no change to EWS for on-premises Exchange Server[^10]. The 15SU4 release notes state that the Graph API migration applies only to Office 365[^47]. Integrations with Exchange 2016 and Exchange 2019 continue to use EWS[^47]. **Azure app registration.** For Office 365 unified messaging over Microsoft Graph, the Azure app registration needs the application (not delegated) permissions Mail.ReadWrite and Mail.Send, with admin consent granted[^13]. Calendars.ReadWrite and Contacts.ReadWrite are needed only for calendar and contact access[^13]. **After the upgrade.** When the upgrade to 15SU4 or later converts an Office 365 unified messaging service from EWS to Graph API, the service may need up to 4 hours to become fully stable[^12]. Open caveats in 15SU4 describe Graph API failures[^45][^46]: - CSCwt99240 describes Mailbox Sync failing with an invalid Graph API URL after upgrade when Active Directory Site Name was not set to empty on the unified messaging service page before upgrading[^45]. - CSCwu52456, a severity 2 caveat, describes unified messaging not working with Graph API because of a parsing failure in the JSON response from Office 365[^46]. ## Sending mail through Microsoft 365 **Client SMTP submission.** For client SMTP submission to Exchange Online, Microsoft specifies the following[^22]: - Smart host smtp.office365.com, not an IP address[^22]. - TCP 587 (recommended) or 25[^22]. - STARTTLS with TLS 1.2 or 1.3[^22]. - The credentials of a licensed mailbox[^22]. SMTP AUTH is disabled by default for Microsoft 365 organizations created after January 2020 and must be enabled per mailbox for client SMTP submission[^23]. Basic-auth SMTP submission is incompatible with Microsoft Entra ID security defaults[^23]. Microsoft states that client SMTP submission with Basic authentication in Exchange Online is scheduled for deprecation[^19]. Microsoft lists these alternatives[^19]: - High Volume Email, for internal recipients[^19]. - Azure Communication Services Email[^19]. - Relaying through an on-premises mail server[^19]. **SMTP relay through a connector.** Microsoft 365 SMTP relay uses the tenant MX endpoint on port 25 and authenticates through an inbound connector[^21]. The connector uses either a TLS certificate whose Subject/SAN matches an accepted domain or a static, unshared public IP[^21]. SMTP relay needs no licensed mailbox and can relay to external recipients[^21]. **Direct Send.** Microsoft 365 Direct Send is unauthenticated, uses the MX endpoint on port 25, and delivers only to the tenant's own recipients[^20]. Mail to external recipients is rejected[^20]. Microsoft says it is working on an option to disable Direct Send by default[^20]. ## Choosing micro traces Cisco warns that enabling Unity Connection Serviceability micro traces decreases system performance and that traces should be enabled only for troubleshooting[^51]. | Problem | Micro trace and service | Log files | |---|---|---| | Message relay[^52] | MTA (all levels) on Connection Message Transfer Agent; SMTP (all levels) on Connection SMTP Server | diag_MTA_*.uc; diag_SMTP_*.uc | | SMTP, HTML and intelligent notification[^53] | Notifier (all levels except 6 and 7) on Connection Notifier; SMTP (all levels) on Connection SMTP Server | diag_CuNotifier_*.uc; diag_SMTP_*.uc | | Single inbox messages not synchronised[^50] | CsMbxSync (all levels) on Connection Mailbox Sync | diag_CuMbxSync_*.uc | The notification-devices chapter gives narrower guidance for SMTP notification delivery problems[^44]. It recommends SMTP micro trace levels 10, 11, 12 and 13, with level 18 adding network message detail[^44]. ## See also See also [Setting up Unity Connection single inbox with Microsoft 365](https://warmtransfer.net/knowledge/unity-connection-single-inbox-setup). See also [Cisco Unity Connection voicemail and migration](https://warmtransfer.net/knowledge/cucm-unity-connection). See also [Troubleshooting Unity Connection voicemail login and PIN failures](https://warmtransfer.net/knowledge/unity-connection-login-troubleshooting). See also [Unity Connection user and mailbox exports and reports](https://warmtransfer.net/knowledge/unity-connection-user-exports). ## Applicability Applies to: Cisco Unity Connection and Microsoft Exchange Online. Deployments: on-premises and multi-tenant. Sources checked 2026-10-02. Secure and authenticated SMTP from Unity Connection to a smart host applies from 14SU2 onward[^42]. FN74365 applies to Unity Connection 14 through 14SU6 and to Unity Connection 15 releases earlier than 15SU4[^7]. The Graph API folder synchronisation scope applies to 15SU4 and later[^11]. The Microsoft mail-submission guidance in this article concerns Exchange Online[^22]. ## What remains uncertain Whether a later service update resolves the 15SU4 open caveats CSCwt99240 and CSCwu52456 is not covered by the sources below. The date on which Basic authentication for client SMTP submission will be removed in Exchange Online is not covered by the sources below. Whether Unity Connection's smart host client has been validated against each Microsoft 365 sending method is not covered by the sources below. ## Sources [^1]: Single inbox with Office 365 may not work when the Unity Connection service account was created in on-premises Active Directory and synchronised to Office 365, because Unity Connection cannot handle ADFS. Cisco's fix is to create the account locally in Office 365. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0110.html), Troubleshooting Unified Messaging > Office 365 ADFS note. Checked 2026-10-02. [^2]: Notification devices added in Unity Connection Administration are active at all hours by default, so users may be notified at unexpected times until a schedule is set in the Cisco PCA. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Notification Devices](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_010000.html), Notification Devices Trigger at Unexpected Times. Checked 2026-10-02. [^3]: A malformed message goes into the MTA bad mail folder (UmssMtaBadMail) rather than to the Undeliverable Messages list. Unity Connection checks that folder nightly and logs an error when it finds messages there. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Messages](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0101.html), Troubleshooting Messages > bad mail folder. Checked 2026-10-02. [^4]: Unity Connection has eight default notification devices that cannot be deleted: Pager, Work Phone, Home Phone, Mobile Phone, SMTP, HTML, HTML Missed Call and HTML Scheduled Summary. Cisco says not to change their display names. Source: [System Administration Guide for Cisco Unity Connection Release 15 - Notifications](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/design/b_15cucsag/b_12xcucsag_chapter_01101.html), Notifications > Default Notification Devices. Checked 2026-10-02. [^5]: Microsoft's EWS deprecation timeline says EWS starts to be disabled globally for all Exchange Online organizations in October 2026 and is fully disabled in April 2027. Source: [Deprecation of Exchange Web Services in Exchange Online](https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/deprecation-of-ews-exchange-online), EWS deprecation timeline > October 2026 / April 2027 bullets. Checked 2026-10-02. [^6]: The On Notification Failure > Send To failover option used to cover missed phone/pager notification attempts is not available for SMTP notification devices. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Notification Devices](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_010000.html), Message Notification Is Slow for a Single User > missed notification attempts. Checked 2026-10-02. [^7]: Field Notice FN74365 (revision 1.0, 15 April 2026) lists Unity Connection 14 (all releases through 14SU6) and Unity Connection 15 releases earlier than 15SU4 as affected by the Exchange Online EWS deprecation for unified messaging with Microsoft 365. Source: [Field Notice: FN74365 - Cisco Unity Connection Unified Messaging with Microsoft 365 - Voicemail Stored in Cisco Unity Connection Will Not Sync with Exchange Online (Outlook) Due to EWS Deprecation - Software Upgrade Recommended](https://www.cisco.com/c/en/us/support/docs/field-notices/743/fn74365.html), FN74365 > Products Affected. Checked 2026-10-02. [^8]: FN74365's remedy is to upgrade Unity Connection to 15SU4 or later, which uses Microsoft Graph API for Office 365, before 1 October 2026, when Microsoft begins blocking EWS requests from non-Microsoft apps. Source: [Field Notice: FN74365 - Cisco Unity Connection Unified Messaging with Microsoft 365 - Voicemail Stored in Cisco Unity Connection Will Not Sync with Exchange Online (Outlook) Due to EWS Deprecation - Software Upgrade Recommended](https://www.cisco.com/c/en/us/support/docs/field-notices/743/fn74365.html), FN74365 > Workaround/Solution. Checked 2026-10-02. [^9]: Per FN74365, affected systems fail to synchronise voicemail with Exchange Online and the admin console reports 'Failed to Connect to Microsoft endpoint using https://outlook.office365.com'. Source: [Field Notice: FN74365 - Cisco Unity Connection Unified Messaging with Microsoft 365 - Voicemail Stored in Cisco Unity Connection Will Not Sync with Exchange Online (Outlook) Due to EWS Deprecation - Software Upgrade Recommended](https://www.cisco.com/c/en/us/support/docs/field-notices/743/fn74365.html), FN74365 > Problem Symptom. Checked 2026-10-02. [^10]: FN74365 states the EWS deprecation applies only to Exchange Online; there is no change to EWS for on-premises Exchange Server. Source: [Field Notice: FN74365 - Cisco Unity Connection Unified Messaging with Microsoft 365 - Voicemail Stored in Cisco Unity Connection Will Not Sync with Exchange Online (Outlook) Due to EWS Deprecation - Software Upgrade Recommended](https://www.cisco.com/c/en/us/support/docs/field-notices/743/fn74365.html), FN74365 > Problem Description note. Checked 2026-10-02. [^11]: In 15SU4 and later, single inbox message synchronisation covers only the default Outlook folders Inbox, Junk Email and Deleted Items. Voicemails in user-created subfolders are outside the supported scope and are treated as deleted. Source: [Unified Messaging Guide for Cisco Unity Connection Release 15 - Introduction to Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/unified_messaging/guide/b_15cucumgx/b_15cucumgx_chapter_00.html), Introduction to Unified Messaging > Single Inbox > synchronization scope. Checked 2026-10-02. [^12]: After the upgrade to 15SU4 or later converts an Office 365 unified messaging service from EWS to Graph API, the service may need up to 4 hours to become fully stable. Source: [Unified Messaging Guide for Cisco Unity Connection Release 15 - Configuring Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/unified_messaging/guide/b_15cucumgx/b_15cucumgx_chapter_01.html), Configuring Unified Messaging > Office 365 with Microsoft Graph API > upgrade note. Checked 2026-10-02. [^13]: For Office 365 unified messaging over Microsoft Graph, the Azure app registration needs the application (not delegated) permissions Mail.ReadWrite and Mail.Send, with admin consent granted. Calendars.ReadWrite and Contacts.ReadWrite are needed only for calendar and contact access. Source: [Unified Messaging Guide for Cisco Unity Connection Release 15 - Configuring Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/unified_messaging/guide/b_15cucumgx/b_15cucumgx_chapter_01.html), Configuring Unified Messaging > Office 365 with Microsoft Graph API > registering the application on the Azure portal. Checked 2026-10-02. [^14]: Voice messages can be attached to HTML notifications only when the administrator enables 'Allow voice mail as attachments to HTML notifications'; the default maximum attachment size is 2048 KB, and secure or private messages cannot be sent as attachments. Source: [System Administration Guide for Cisco Unity Connection Release 15 - Notifications](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/design/b_15cucsag/b_12xcucsag_chapter_01101.html), Notifications > HTML notification voice message attachment. Checked 2026-10-02. [^15]: A maximum of three custom HTML-type notification devices can be created per user through the Bulk Administration Tool. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Notification Devices](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_010000.html), HTML notifications not working. Checked 2026-10-02. [^16]: The HTML notifications troubleshooting chapter says to confirm that the Unity Connection Notifier service is up and running. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting the HTML Notifications](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_011100.html), Troubleshooting the HTML Notifications > services status. Checked 2026-10-02. [^17]: For HTML notifications not arriving, Cisco's checklist is: the HTML notification device is enabled on the user, its email address is present and correct, an SMTP smart host is configured, and the Connection SMTP Server and Connection Notifier services are running. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Notification Devices](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_010000.html), Notification Devices Not Working at All > HTML notifications not working. Checked 2026-10-02. [^18]: Unity Connection's documented smart host authentication is a username and password, and no OAuth option was found. So a Unity Connection smart host pointed at smtp.office365.com with Use Authentication likely depends on Basic-auth SMTP AUTH and is exposed to Microsoft's retirement of it (inferred). Source: [Cisco Unity Connection Provisioning Interface (CUPI) API for SMTP Configuration](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/REST-API/CUPI_API/b_CUPI-API/m_smtp_configuration.html), SMTP client configuration field table (isAuthEnabled, smtpUsername, smtpPassword); combined with ms-learn-mfd-app-send-email-m365 Basic auth note. Checked 2026-10-02. [^19]: Microsoft states that client SMTP submission with Basic authentication in Exchange Online is scheduled for deprecation. Its listed alternatives are High Volume Email (internal recipients), Azure Communication Services Email, or relaying through an on-premises mail server. Source: [How to set up a multifunction device or application to send email using Microsoft 365 or Office 365](https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-microsoft-365-or-office-365), Client SMTP submission > Note on Basic authentication deprecation. Checked 2026-10-02. [^20]: Microsoft 365 Direct Send (unauthenticated, MX endpoint, port 25) delivers only to the tenant's own recipients; mail to external recipients is rejected. Microsoft says it is working on an option to disable Direct Send by default. Source: [How to set up a multifunction device or application to send email using Microsoft 365 or Office 365](https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-microsoft-365-or-office-365), Direct Send > Note; Features/Limitations of Direct Send. Checked 2026-10-02. [^21]: Microsoft 365 SMTP relay uses the tenant MX endpoint on port 25 and authenticates through an inbound connector, using a TLS certificate whose Subject/SAN matches an accepted domain or a static, unshared public IP. It needs no licensed mailbox and can relay to external recipients. Source: [How to set up a multifunction device or application to send email using Microsoft 365 or Office 365](https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-microsoft-365-or-office-365), SMTP relay: Configure a connector to relay email ... (requirements and settings tables). Checked 2026-10-02. [^22]: For client SMTP submission to Exchange Online, Microsoft specifies smart host smtp.office365.com (not an IP address), TCP 587 (recommended) or 25, STARTTLS with TLS 1.2 or 1.3, and the credentials of a licensed mailbox. Source: [How to set up a multifunction device or application to send email using Microsoft 365 or Office 365](https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-microsoft-365-or-office-365), Client SMTP submission > Set up client SMTP submission (settings table). Checked 2026-10-02. [^23]: SMTP AUTH is disabled by default for Microsoft 365 organizations created after January 2020 and must be enabled per mailbox for client SMTP submission. Basic-auth SMTP submission is incompatible with Microsoft Entra ID security defaults. Source: [How to set up a multifunction device or application to send email using Microsoft 365 or Office 365](https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-microsoft-365-or-office-365), Client SMTP submission > Tip (SMTP AUTH enabled for the designated mailbox); security defaults sentence. Checked 2026-10-02. [^24]: For Exchange sync delays, Cisco recommends CsMbxSync micro trace level 19 to watch outstanding requests, which should not exceed 999. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0110.html), Troubleshooting Unified Messaging > synchronization delays (Exchange). Checked 2026-10-02. [^25]: When a Unity Connection notification device does not work at all, the first checks are that the device's Enabled check box is selected and that its notification schedule is active at the time notification should occur. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Notification Devices](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_010000.html), Troubleshooting Notification Devices > Notification Devices Not Working at All. Checked 2026-10-02. [^26]: A notification device triggers only for the message types selected in its Notification Rule Events; for example a device set to trigger on urgent voice messages only does not fire for regular voice messages. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Notification Devices](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_010000.html), Notification Devices Not Working at All > incorrect message types configured. Checked 2026-10-02. [^27]: EvtMbxOAuthHttpStatusCode 0 in CiscoSysLog points to the Proxy Server and Active Directory DNS Domain Name settings on the unified messaging service. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0110.html), Troubleshooting Unified Messaging > OAuth2 events in CiscoSysLog. Checked 2026-10-02. [^28]: EvtMbxOAuthHttpStatusCode 401 in CiscoSysLog means the Application ID, Client ID and Client Secret values on the unified messaging service should be verified. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0110.html), Troubleshooting Unified Messaging > OAuth2 events in CiscoSysLog. Checked 2026-10-02. [^29]: For Office 365 OAuth, the CiscoSysLog event EvtMbxOAuthAccessTokenDBSaveSuccess confirms a successful token refresh and is expected roughly every 50 minutes. If EvtMbxOAuthAccessTokenRefreshThreadFailed appears instead, the Connection Mailbox Sync service should be restarted. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0110.html), Troubleshooting Unified Messaging > OAuth2 events in CiscoSysLog. Checked 2026-10-02. [^30]: When notification is slow for many users, Cisco says to run the Port Activity Report (Serviceability > Tools > Reports) and, if notification port usage exceeds 70 percent at peak, configure additional ports for message notification; below 70 percent, contact Cisco TAC. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Notification Devices](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_010000.html), Message Notification Is Slow for Multiple Users > inadequate notification ports. Checked 2026-10-02. [^31]: Cisco technote 117705 attributes relay failures with the Relay or Accept & Relay actions to misconfigured SMTP proxy addresses. In that case the SMTP log shows 'Pickup Folder Monitor: No New Messages found', and the fix is a correct SMTP proxy address on each user or VPIM contact. Source: [CUC Message Relay Failure Due to Incorrectly Configured SMTP Proxy Addresses](https://www.cisco.com/c/en/us/support/docs/unified-communications/unity-connection/117705-technote-CUC-00.html), Technote 117705 > Problem / Solution. Checked 2026-10-02. [^32]: Unity Connection will not relay a message when the relay address matches a user's SMTP proxy address, to avoid delivery loops. Cisco recommends using the precise address of the destination mailbox (for example alias@mailserver) as the relay address. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Messages](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0101.html), Troubleshooting Messages > Unity Connection Unable to Relay Messages. Checked 2026-10-02. [^33]: Unity Connection sends a non-delivery receipt to the sender when it cannot relay a message because the message is marked private or secure. Relaying such messages requires the separate checkboxes under System Settings > Advanced > Messaging. Source: [System Administration Guide for Cisco Unity Connection Release 15 - Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/design/b_15cucsag/b_12xcucsag_chapter_01010.html), Messaging > Relaying Messages to Smart Host (Note on private/secure messages). Checked 2026-10-02. [^34]: If Unity Connection cannot relay a message to the correct address, Cisco says to make sure the smart host entered on the server is correct and reachable and to review the message relay logs. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Messages](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0101.html), Troubleshooting Messages > Unity Connection Unable to Relay Messages. Checked 2026-10-02. [^35]: Notification device schedules are changed in the Cisco Personal Communications Assistant, not in Unity Connection Administration; Administration reaches it via the device page's Edit Notification Device Details link. An inactive schedule is the documented cause of intermittent notification. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Notification Devices](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_010000.html), Message Notification Is Intermittent. Checked 2026-10-02. [^36]: With single inbox, secure messages are stored only on the Unity Connection server, and only a decoy message explaining secure messages is replicated to Exchange. Source: [Unified Messaging Guide for Cisco Unity Connection Release 15 - Introduction to Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/unified_messaging/guide/b_15cucumgx/b_15cucumgx_chapter_00.html), Introduction to Unified Messaging > secure messages and single inbox. Checked 2026-10-02. [^37]: In SMS notification traces, 'SmppConnect failed' indicates Unity Connection could not connect to the SMPP provider, 'SmppBindTransmitter failed' indicates an authentication failure with the provider, and 'SmppSubmitSm failed' indicates message submission to the provider failed. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Notification Devices](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_010000.html), SMS notifications not working > error list. Checked 2026-10-02. [^38]: For SMS notification failures Cisco directs administrators to verify the provider settings under System Settings > Advanced > SMPP Providers against the provider's specification and to enable the SMS Device micro trace at level 30. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Notification Devices](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_010000.html), Notification Devices Not Working at All > SMS notifications not working. Checked 2026-10-02. [^39]: Cisco says not to configure SMTP devices in a chained message notification except as the last device, because Unity Connection does not detect notification failure for SMTP devices. Source: [System Administration Guide for Cisco Unity Connection Release 15 - Notifications](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/design/b_15cucsag/b_12xcucsag_chapter_01101.html), Notifications > chaining message notification (Note). Checked 2026-10-02. [^40]: When SMTP notifications fail for multiple users, Cisco says to confirm a smart host is set at System Settings > SMTP Configuration > Smart Host, that the smart host accepts messages from the Unity Connection server, and that the Connection SMTP Server and Connection Notifier services are running. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Notification Devices](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_010000.html), Notification Devices Not Working at All > SMTP message notification not working for multiple users. Checked 2026-10-02. [^41]: Per the CUPI SMTP client API, with IsClientSecure unchecked Unity Connection connects to the smart host on port 25 without STARTTLS, and with IsClientSecure checked it connects on port 587 using STARTTLS. Source: [Cisco Unity Connection Provisioning Interface (CUPI) API for SMTP Configuration](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/REST-API/CUPI_API/b_CUPI-API/m_smtp_configuration.html), SMTP client configuration > IsClientSecure field description. Checked 2026-10-02. [^42]: Secure (STARTTLS) and authenticated SMTP client communication from Unity Connection to a smart host is supported from Unity Connection 14SU2 onward. Source: [Cisco Unity Connection Provisioning Interface (CUPI) API for SMTP Configuration](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/REST-API/CUPI_API/b_CUPI-API/m_smtp_configuration.html), SMTP client configuration > product requirement statement. Checked 2026-10-02. [^43]: To use secure SMTP to a smart host, the administrator selects Enable Secure Client on System Settings > SMTP Configuration > Smart Host, sets the secure Host Port, and optionally enables Use Authentication with the smart host username and password, then saves and restarts services. Source: [System Administration Guide for Cisco Unity Connection Release 15 - Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/design/b_15cucsag/b_12xcucsag_chapter_01010.html), Messaging > Over STARTTLS on Port 25 and 587 using Authentication Support. Checked 2026-10-02. [^44]: For SMTP notification delivery problems the notification-devices chapter recommends SMTP micro trace levels 10, 11, 12 and 13, with level 18 adding network message detail. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Notification Devices](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_010000.html), SMTP message notification not working for multiple users > trace guidance. Checked 2026-10-02. [^45]: CSCwt99240, an open caveat in 15SU4, describes Mailbox Sync failing with an invalid Graph API URL after upgrade when Active Directory Site Name was not set to empty on the unified messaging service page before upgrading. Source: [Release Notes for Cisco Unity Connection Release 15 Service Update 4](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/readme/b_15su4cucrn.html), Open Caveats—Unity Connection Release 15SU4 > CSCwt99240. Checked 2026-10-02. [^46]: CSCwu52456, a severity 2 open caveat in 15SU4, describes unified messaging not working with Graph API because of a parsing failure in the JSON response from Office 365. Source: [Release Notes for Cisco Unity Connection Release 15 Service Update 4](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/readme/b_15su4cucrn.html), Open Caveats—Unity Connection Release 15SU4 > CSCwu52456. Checked 2026-10-02. [^47]: The 15SU4 release notes state that the Graph API migration applies only to Office 365, and that integrations with Exchange 2016 and Exchange 2019 continue to use EWS. Source: [Release Notes for Cisco Unity Connection Release 15 Service Update 4](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/readme/b_15su4cucrn.html), Release Notes 15SU4 > Microsoft Graph API support for Office 365. Checked 2026-10-02. [^48]: For Exchange single inbox synchronisation delays, Cisco says to verify the Connection Jetty service is started and that the Exchange server can reach Unity Connection on TCP port 7080. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0110.html), Troubleshooting Unified Messaging > synchronization delays (Exchange). Checked 2026-10-02. [^49]: Whether Unity Connection can run STARTTLS to a smart host on port 25 is unclear. The admin guide heading and the CUPI requirement both mention secure communication on ports 25 and 587, but the CUPI IsClientSecure description ties secure mode to port 587 and non-secure mode to port 25 (inferred). Source: [Cisco Unity Connection Provisioning Interface (CUPI) API for SMTP Configuration](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/REST-API/CUPI_API/b_CUPI-API/m_smtp_configuration.html), IsClientSecure field description vs product requirement statement; compare cisco-cuc15-sag-messaging 'Over STARTTLS on Port 25 and 587' heading. Checked 2026-10-02. [^50]: For single inbox messages not synchronised, the micro trace table specifies CsMbxSync (all levels) for the Connection Mailbox Sync service, with logs in diag_CuMbxSync_*.uc. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Cisco Unity Connection](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_00.html), Micro Traces for Selected Problems table > Unified messaging: messages not synchronized row. Checked 2026-10-02. [^51]: Cisco warns that enabling Unity Connection Serviceability micro traces decreases system performance and that traces should be enabled only for troubleshooting. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Cisco Unity Connection](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_00.html), Diagnostic traces > micro traces caution. Checked 2026-10-02. [^52]: For message relay problems Cisco's micro trace table specifies MTA (all levels) for the Connection Message Transfer Agent service, logged to diag_MTA_*.uc, and SMTP (all levels) for the Connection SMTP Server service, logged to diag_SMTP_*.uc. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Cisco Unity Connection](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_00.html), Micro Traces for Selected Problems table > Message relay issues row. Checked 2026-10-02. [^53]: For SMTP, HTML and intelligent notification problems the micro trace table specifies Notifier (all levels except 6 and 7) on the Connection Notifier service (diag_CuNotifier_*.uc) plus SMTP (all levels) on the Connection SMTP Server service (diag_SMTP_*.uc). Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Cisco Unity Connection](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_00.html), Micro Traces for Selected Problems table > Notification issues: SMTP/HTML notification row. Checked 2026-10-02. [^54]: A 401 error in unified messaging testing can be caused by a wrong password, a wrong username or a wrongly formatted username on the unified messaging services account. It can also mean the authentication mode configured in Unity Connection does not match Exchange. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0110.html), Troubleshooting Unified Messaging > 401 error. Checked 2026-10-02. [^55]: A 403 error indicates SSL is required by Exchange or Office 365 but the public CA certificates that signed the Exchange server certificates have not been uploaded to Unity Connection. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0110.html), Troubleshooting Unified Messaging > 403 error. Checked 2026-10-02. [^56]: For Gmail (Google Workspace) single inbox failing for all users, the service to check in Critical Services is Connection Google Workspace Sync. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0110.html), Troubleshooting Unified Messaging > Single Inbox Not Working for Any Users (Gmail). Checked 2026-10-02. [^57]: If single inbox is not working for any user with Exchange or Office 365, Cisco says to confirm in Cisco Unity Connection Serviceability that the Connection Mailbox Sync service (Critical Services) is Started. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0110.html), Troubleshooting Unified Messaging > Single Inbox Not Working for Any Users. Checked 2026-10-02. [^58]: Unity Connection provides a Test button both on the unified messaging service (Unified Messaging > Unified Messaging Services) and on each user's unified messaging account; the Task Execution Results page identifies configuration problems. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0110.html), Troubleshooting Unified Messaging > testing the unified messaging service / account. Checked 2026-10-02. [^59]: Resetting a unified messaging service delays synchronisation for every user associated with that service while Unity Connection resynchronises, so per-user account reset should be tried first. Source: [Troubleshooting Guide for Cisco Unity Connection Release 15 - Troubleshooting Unified Messaging](https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/15/troubleshooting/guide/b_15cuctsg/b_15cuctsg_chapter_0110.html), Troubleshooting Unified Messaging > synchronization delays (Office 365 / Gmail). Checked 2026-10-02.