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.
Checked 2026-10-02
- Vendor
- Microsoft
- Product
- Exchange Online
- Subsystem
- Direct Send
- Deployment
- multi-tenant
- Region
- not restricted
- Release range
- current as of 2026-10-02
- Checked
- 2026-10-02
Sources
- How to set up a multifunction device or application to send email using Microsoft 365 or Office 365 — Microsoft · tier 2 current vendor documentation · Direct Send > Note; Features/Limitations of Direct Send
Cite this note
APA
WarmTransfer. (2026, October 2). Troubleshooting Unity Connection voicemail-to-email and notifications: source note unity-connection-notification-troubleshooting-m365-direct. WarmTransfer. https://warmtransfer.net/knowledge/claims/unity-connection-notification-troubleshooting-m365-direct
BibTeX
@misc{warmtransfer-claim-unity-connection-notification-troubleshooting-m365-direct,
title = {Troubleshooting Unity Connection voicemail-to-email and notifications: source note unity-connection-notification-troubleshooting-m365-direct},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/unity-connection-notification-troubleshooting-m365-direct},
note = {Source note unity-connection-notification-troubleshooting-m365-direct, checked 2026-10-02}
}