WarmTransfer
emergency calling · published

Troubleshooting 911 calls that route with the wrong location

Verified 2026-10-01 · 60 sources · tier 1–2

Also known as e911-wrong-location.

Troubleshooting 911 calls that route with incorrect location information requires examining regulatory definitions, platform network discovery rules, and provider routing headers 8​36​2. In the United States, federal rules establish specific requirements for dispatchable location across multi-line telephone systems (MLTS) and interconnected VoIP services 10​14.

Regulatory requirements for emergency location

Under 47 CFR 9.3, a dispatchable location delivered to the Public Safety Answering Point (PSAP) consists of the calling party's validated street address plus additional details such as a suite or apartment to identify the location, with commercial mobile radio service (CMRS) providers excepted 8. Alternative location information under 47 CFR 9.3 can be coordinate-based and must identify the caller's civic address and approximate in-building location, including floor level in large buildings 7.

For MLTS deployments, 47 CFR 9.16(b)(1) mandates direct 911 dialing without prefixes, post-fixes, or extra digits 9. Contemporaneous notification to a central point or designated person without delaying the call is required by 47 CFR 9.16(b)(2) where technically feasible without improvements 12. Furthermore, 47 CFR 9.16(b)(3) established a compliance date of January 6, 2021, for automated dispatchable location on on-premises fixed MLTS devices 10.

Interconnected VoIP obligations depend on service mobility:

  • Fixed interconnected VoIP providers have been required to deliver an automated dispatchable location with each 911 call since January 6, 2021 14.
  • For non-fixed interconnected VoIP, since January 6, 2022, 47 CFR 9.11(b)(4)(ii) requires automated dispatchable location if technically feasible; if not, providers must use a Registered Location, alternative location information, or route the call to a national emergency call center 15.

Microsoft Teams dynamic emergency location troubleshooting

Client discovery and network matching

A Teams client sends its network connectivity information in a location request at startup, periodically thereafter, and whenever its network connection changes 39. When evaluating the Location Information Service (LIS), the first matching network element wins in this order: wireless access point, Ethernet switch/port, Ethernet switch, subnet 36.

Teams evaluates IP-based dynamic policies or location lookups only when the client's external IP matches an address in the tenant's trusted IP list; however, switch/port (LLDP) and BSSID lookups occur regardless of a trusted IP match 46. Microsoft notes that some network configuration updates take up to 4 hours to propagate to clients 40. Deployments using cloud proxies that alter the client's source IP do not support network configuration lookups for dynamic emergency calling 23.

For subnet matching, Teams calculates a network ID using the client's IP and client-reported prefix length, which must match the subnet configured in LIS (for instance, 10.10.10.150/25 yields 10.10.10.128) 37. A Windows client using a stateful DHCPv6 address can report a /128 prefix, causing Teams LIS to compute the full address as the network ID, which fails to match a /64 LIS subnet entry 35. In addition, Microsoft warns that matching a network site and obtaining emergency policies does not confirm the client retrieved an emergency address from LIS 42. Subnets assigned to network sites must also be separately populated in the LIS database to deliver dynamic locations 44.

Client types and address validation

Address assignments to network identifiers require geo codes, and addresses without geo codes cannot be linked to those identifiers 34. Every emergency address must be marked validated prior to assignment to a user or network identifier; addresses created using the map search in the Teams admin center validate automatically 22.

Dynamic emergency calling features vary across client types:

  • Subnet-based locations work across all Teams clients, but Wi-Fi-based locations function on all clients except Teams phones 49.
  • The Teams web client does not support dynamic emergency calling or security desk notifications, and Microsoft suggests turning off Web PSTN calling for these users via calling policy 47.
  • The work-from-home emergency address interface is available on Teams desktop for Windows and Mac; Teams phones do not support it, and Teams mobile supports automatic detection but not user-entered addresses 48. Users can only add, edit, or confirm their address when assigned an emergency calling policy with ExternalLocationLookupMode enabled 33.

Routing precedence and Direct Routing mechanics

Teams uses this location precedence for an emergency call: admin-defined LIS dynamic address; user-confirmed or edited address tied to the current network; OS-suggested address; user-entered address without service resolution; admin static address on the user's number 38.

In the United States, an emergency call carrying only an address statically assigned to the user or number, or an emergency call with no address, is screened before transfer to the PSAP 45. An OS-suggested address that has not been confirmed by the user is likewise screened, whereas a user-confirmed address routes directly 41. WarmTransfer's reading of the sources is that a remote worker on an untrusted network lacking LLDP or BSSID data will miss an LIS match, falling back to OS-suggested, user-confirmed, or static addresses, with static-only entries resulting in screening 20.

If emergency calling policies are applied to both a user and a network site, the site policy takes precedence while the user is connected at that site 43. For Direct Routing users, emergency calls fall back to the user's policy when the site lacks a policy, the site is undefined, or the dialed number does not match the site policy's dial strings 32. If a Direct Routing client cannot obtain an emergency call routing policy from either its site or user account, the user is not enabled for emergency calling 30.

For Direct Routing configurations:

  • Dynamic location routing is supported in the United States, and in Canada where all emergency calls are screened nationally prior to PSAP transfer 25.
  • Direct Routing dynamic emergency calling requires an SBC configured with an Emergency Location Identification Number (ELIN) application or a connection to an Emergency Routing Service provider in the US and Canada 28.
  • The SBC's PidfloSupported setting must be set to True on the PSTN gateway to attach location data to the SIP INVITE 31.
  • Voice route dial patterns must not include a leading '+' because Teams clients transmit Direct Routing emergency calls without that prefix 29.
  • When an SBC ELIN application is used, the SBC substitutes the caller's number with the ELIN based on the dynamic location, and reverses the mapping if the PSAP calls back 27. These ELIN records must be uploaded to the PSTN emergency database, and Teams emergency locations configured with an ELIN identifier must match the records inside the SBC application 26.

Other platform behaviors

Cisco Webex Calling and Emergency Responder

On Webex Calling using RedSky:

  • HELD-capable Cisco MPP phones determine location by matching upstream LLDP switch data, WAP BSSID, IP address, or MAC addresses to the RedSky network map 56.
  • Non-HELD devices rely on the caller ID transmitted in the call 58.
  • The Webex App desktop client gathers BSSID, IP address, and default gateway MAC while ignoring VPN and virtual adapters 51. When off-premises, the app prompts for an address only upon connecting to an unfamiliar network, reusing stored entries when reconnecting to known networks 52.
  • If no location can be found, RedSky routes the call to a relay center where agents verbally prompt the caller for location details 57.
  • Webex Calling emergency callback numbers (ECBN) can be configured to the user's number, the location default ECBN, or another number assigned within that location 53.
  • Location-level ELIN expiration ranges from 10 to 1440 minutes (defaulting to 60 minutes), during which an assigned ELIN cannot be modified, deleted, or moved 54. If no ELIN is available, the system falls back to the configured ECBN 55.

In on-premises Cisco environments, Cisco Field Notice FN74155 reports that Cisco Emergency Responder 15SU1 with IP subnet tracking may end the subnet search early and route emergency calls with the default ERL instead of the caller's ERL and ELIN 17. Cisco's remedy for FN74155 is upgrading to Cisco Emergency Responder 15SU1a (15.0.1.11901-3) or applying the COP file ciscocm.cer-V15SU1_ip-subnet-tracking_C0218-1.cop.sha512 18.

Zoom Phone and carrier SIP routing

In Zoom Phone, nomadic emergency services prompt the user to confirm or update their address whenever a previously unseen network (IP or MAC) is encountered, or to enter one if no match is present 60. For Zoom Phone BYOC numbers routing emergency calls across the BYOC carrier, the address reported to the PSAP originates from the BYOC carrier's records 59.

Bandwidth identifies the 911 calling number from P-Charge-Info if enabled, then P-Asserted-Identity (if set on the trunk group), then Remote-Party-ID, then From 2. If no usable calling number is identified in these headers, Bandwidth applies a generic callback number and forwards the call to its Emergency Call Center 3.

Testing emergency location routing

US and Canadian users on Teams Calling Plan, Operator Connect, and Teams Phone Mobile can call 933 to reach an automated bot that reads back the calling line ID, emergency address, and whether an actual emergency call would route directly or undergo screening 21. Microsoft directs US Direct Routing customers to use testing services supplied by their Emergency Routing Service Provider rather than the native 933 bot 24. Cisco similarly advises placing test calls to 933—which reads out the caller ID and device address—before enabling full 911 routing on Webex Calling with RedSky 50. On Bandwidth, 933 calls play back the provisioned number and address without routing to a PSAP 1. WarmTransfer's reading of the sources is that while a successful 933 call confirms the provisioned record for that calling number, it does not validate PSAP routing, ALI delivery, or internal security desk alerts 19.

See also

Applicability

Applies to: Microsoft Teams Phone, Microsoft Teams Phone Direct Routing, Cisco Webex Calling, Cisco Webex App, Cisco Emergency Responder, Zoom Phone, and Bandwidth 911 Access. Deployments: on-premises, multi-tenant, carrier-service, and regulatory. Sources checked 2026-10-01.

What remains uncertain

Specific differences in carrier address validation requirements outside of Bandwidth are not covered by the sources below. Location discovery behavior on Linux desktop operating systems is not covered by the sources below.

See also

Related to

Troubleshoots

Referenced by

Sources

  1. 1
    On Bandwidth's 911 service, 933 test calls play back the phone number and address provisioned in the 911 Access Portal and do not reach a PSAP.
    E911 for Static VoIP integration & testing guide · E911 for Static VoIP integration & testing guide > Make a 933 call · Checked 2026-10-01
  2. 2
    Bandwidth identifies the 911 calling number from P-Charge-Info if enabled, then P-Asserted-Identity (if set on the trunk group), then Remote-Party-ID, then From.
    E911 for Static VoIP integration & testing guide · E911 for Static VoIP integration & testing guide > Supported privacy types · Checked 2026-10-01
  3. 3
    On Bandwidth, a 911 call with no usable calling number in the inspected headers receives a generic callback number and is passed to the Emergency Call Center for processing.
    E911 for Static VoIP integration & testing guide · E911 for Static VoIP integration & testing guide > Supported privacy types · Checked 2026-10-01
  4. 4
    A Cisco Emergency Responder PSAP callback can miss the original caller when the ELIN mapping is overwritten by later calls; Cisco advises defining more ELINs per ERL if call volume exceeds the ELIN count.
    Cisco Emergency Responder Administration Guide, Release 15 and SUs - Troubleshoot Cisco Emergency Responder · Troubleshoot Cisco Emergency Responder > PSAP callback subsection · Checked 2026-10-01
  5. 5
    In Cisco Emergency Responder, if the route pattern for the caller's ERL fails, the default ERL's route pattern is used, so the call presents the default ERL's ELIN.
    Cisco Emergency Responder Administration Guide, Release 15 and SUs - Troubleshoot Cisco Emergency Responder · Troubleshoot Cisco Emergency Responder > ELIN for default ERL used for calls from other ERLs · Checked 2026-10-01
  6. 6
    For Cisco Emergency Responder calls reaching the wrong PSAP, Cisco's checks include the ELIN assigned to the ERL, calling-party transformations that alter the ELIN, the ELIN route pattern's gateway, and the provider's ALI record for the ELIN.
    Cisco Emergency Responder Administration Guide, Release 15 and SUs - Troubleshoot Cisco Emergency Responder · Troubleshoot Cisco Emergency Responder > emergency calls not routed to the correct PSAP · Checked 2026-10-01
  7. 7
    Under 47 CFR 9.3, alternative location information is location information, which may be coordinate-based, sufficient to identify the caller's civic address and approximate in-building location including floor level in large buildings.
    47 CFR 9.3 Definitions (Code of Federal Regulations, 2024 annual edition) · 47 CFR 9.3, definition 'Alternative location information' · Checked 2026-10-01
  8. 8
    Under 47 CFR 9.3, dispatchable location means a location delivered to the PSAP with a 911 call consisting of the validated street address of the calling party plus additional information such as suite or apartment needed to adequately identify the caller's location (CMRS providers excepted).
    47 CFR 9.3 Definitions (Code of Federal Regulations, 2024 annual edition) · 47 CFR 9.3, definition 'Dispatchable location' · Checked 2026-10-01
  9. 9
    47 CFR 9.16(b)(1) requires an MLTS to be configured so users can dial 911 directly without any additional digit, code, prefix or post-fix.
    47 CFR 9.16 General obligations for 911 dialing, notification, and location (MLTS), 2024 annual edition · 47 CFR 9.16(b)(1); see also 9.16(a)(1) · Checked 2026-10-01
  10. 10
    47 CFR 9.16(b)(3) requires automated dispatchable location for on-premises fixed MLTS devices, with a compliance date of January 6, 2021.
    47 CFR 9.16 General obligations for 911 dialing, notification, and location (MLTS), 2024 annual edition · 47 CFR 9.16(b)(3)(i) · Checked 2026-10-01
  11. 11
    For on-premises non-fixed MLTS devices, 47 CFR 9.16(b)(3) requires automated dispatchable location by January 6, 2022 where technically feasible, otherwise manually updated dispatchable location or alternative location information.
    47 CFR 9.16 General obligations for 911 dialing, notification, and location (MLTS), 2024 annual edition · 47 CFR 9.16(b)(3)(ii) · Checked 2026-10-01
  12. 12
    47 CFR 9.16(b)(2) requires MLTS notification of a 911 call to a central location or designated person where technically feasible without improvements, initiated contemporaneously with the call where feasible, and without delaying the 911 call.
    47 CFR 9.16 General obligations for 911 dialing, notification, and location (MLTS), 2024 annual edition · 47 CFR 9.16(b)(2) · Checked 2026-10-01
  13. 13
    For off-premises MLTS devices, 47 CFR 9.16(b)(3) requires automated dispatchable location by January 6, 2022 where technically feasible, otherwise manually updated dispatchable location or enhanced location information that may be coordinate-based.
    47 CFR 9.16 General obligations for 911 dialing, notification, and location (MLTS), 2024 annual edition · 47 CFR 9.16(b)(3)(iii) · Checked 2026-10-01
  14. 14
    47 CFR 9.11(b)(4)(i) requires providers of fixed interconnected VoIP service to provide automated dispatchable location with each 911 call, applicable from January 6, 2021.
    47 CFR 9.11 E911 service (interconnected VoIP), 2024 annual edition · 47 CFR 9.11(b) introductory text and (b)(4)(i) · Checked 2026-10-01
  15. 15
    For non-fixed interconnected VoIP from January 6, 2022, 47 CFR 9.11(b)(4)(ii) requires automated dispatchable location if technically feasible, otherwise Registered Location, alternative location information, or routing to a national emergency call center.
    47 CFR 9.11 E911 service (interconnected VoIP), 2024 annual edition · 47 CFR 9.11(b)(4)(ii) · Checked 2026-10-01
  16. 16
    47 CFR 9.11 requires interconnected VoIP providers to give end users one or more methods to update their Registered Location, including at least one that needs only the CPE used to access the service.
    47 CFR 9.11 E911 service (interconnected VoIP), 2024 annual edition · 47 CFR 9.11(b)(4)(ii)(B) as reported; Registered Location update requirement · Checked 2026-10-01
  17. 17
    Cisco Field Notice FN74155 reports that Cisco Emergency Responder 15SU1 with IP subnet tracking may end the subnet search early and route emergency calls with the default ERL instead of the caller's ERL and ELIN.
    Field Notice: FN74155 - Cisco Emergency Responder Emergency Location Identification Number Lookup (ELIN) Fails When Making an Emergency Call - Software Upgrade Recommended · FN74155 > Problem Description / Problem Symptom · Checked 2026-10-01
  18. 18
    Cisco's remedy for FN74155 is upgrading to Cisco Emergency Responder 15SU1a (15.0.1.11901-3) or applying the COP file ciscocm.cer-V15SU1_ip-subnet-tracking_C0218-1.cop.sha512.
    Field Notice: FN74155 - Cisco Emergency Responder Emergency Location Identification Number Lookup (ELIN) Fails When Making an Emergency Call - Software Upgrade Recommended · FN74155 > Workaround/Solution · Checked 2026-10-01
  19. 19
    A correct 933 readback confirms the calling number and the address the provider holds for it, but does not exercise PSAP selection, ALI delivery to the PSAP, or security-desk notification.inferred
    E911 for Static VoIP integration & testing guide · Make a 933 call (933 does not reach a PSAP); compare Teams Test emergency calling and Webex testing with 933 · Checked 2026-10-01
  20. 20
    A Teams user working from home on a network not in the tenant's trusted IPs and without LLDP or BSSID entries will not get an LIS match, so the call relies on user-confirmed, OS-suggested or static addresses, and a static-only address is screened.inferred
    Emergency addresses for remote locations · Location precedence and Emergency address classification and routing; combined with Configure dynamic emergency calling > Configure network settings · Checked 2026-10-01
  21. 21
    Teams Calling Plan, Operator Connect and Teams Phone Mobile users in the US or Canada can dial 933, which reaches a bot that reads back the calling line ID, the emergency address, and whether a real call would route automatically to the PSAP or be screened first.
    Configure dynamic emergency calling · Configure dynamic emergency calling > Test emergency calling · Checked 2026-10-01
  22. 22
    A Teams emergency address must be marked validated before it can be assigned to a user or network identifier; addresses created with the Teams admin center map search are validated automatically.
    Plan and manage emergency calling · Plan and manage emergency calling > Emergency address > Emergency address validation · Checked 2026-10-01
  23. 23
    Cloud proxy deployments that modify the source IP address of Teams clients do not support network configuration setting lookups for dynamic emergency calling.
    Configure dynamic emergency calling · Configure dynamic emergency calling > Configure network settings, Important box · Checked 2026-10-01
  24. 24
    Microsoft directs US Direct Routing customers to coordinate with their Emergency Routing Service Provider for a test service rather than offering the 933 bot itself.
    Configure dynamic emergency calling · Configure dynamic emergency calling > Test emergency calling, second bullet · Checked 2026-10-01
  25. 25
    Dynamic location for routing Direct Routing emergency calls is supported in the United States, and in Canada the same way except that all emergency calls are screened nationally before transfer to the PSAP.
    Considerations for Direct Routing · Considerations for Direct Routing > Dynamic emergency calling for Direct Routing · Checked 2026-10-01
  26. 26
    For Direct Routing ELIN deployments, ELIN records must be uploaded to the PSTN emergency database and Teams emergency locations with an ELIN identifier must match those in the SBC ELIN application.
    Considerations for Direct Routing · Considerations for Direct Routing > Emergency Location Identification Number applications, first paragraph · Checked 2026-10-01
  27. 27
    With an SBC ELIN application in Direct Routing, the SBC matches the caller's dynamic location to an ELIN record, substitutes the caller's number with the ELIN, and reverses the substitution on PSAP call-back.
    Considerations for Direct Routing · Considerations for Direct Routing > Emergency Location Identification Number applications · Checked 2026-10-01
  28. 28
    Teams Direct Routing emergency calling requires either a connection to an Emergency Routing Service provider (US and Canada) or an SBC configured with an ELIN application.
    Configure dynamic emergency calling · Configure dynamic emergency calling > Set up an Emergency Routing Service provider · Checked 2026-10-01
  29. 29
    Teams clients no longer send Direct Routing emergency calls with a '+' before the emergency number, so voice route patterns for the emergency dial string must match without the plus.
    Considerations for Direct Routing · Considerations for Direct Routing > Emergency call routing for Direct Routing, Note · Checked 2026-10-01
  30. 30
    If a Teams Direct Routing client cannot obtain any emergency call routing policy from its site or user account, the user is not enabled for emergency calling.
    Considerations for Direct Routing · Considerations for Direct Routing > Emergency call enablement for Direct Routing, third bullet · Checked 2026-10-01
  31. 31
    For Teams Direct Routing dynamic emergency calling, the SBC's PSTN gateway setting PidfloSupported must be True so location is added to the outgoing emergency INVITE.
    Configure dynamic emergency calling · Configure dynamic emergency calling > Emergency calling prerequisites for Direct Routing · Checked 2026-10-01
  32. 32
    For Direct Routing, the user's emergency call routing policy is used when the site has no policy, the client is at an undefined site, or the dialed number matches none of the site policy's emergency numbers.
    Considerations for Direct Routing · Considerations for Direct Routing > Emergency call enablement for Direct Routing, second bullet · Checked 2026-10-01
  33. 33
    End users can only add, edit or confirm their own Teams emergency address when assigned an emergency calling policy with ExternalLocationLookupMode enabled.
    Emergency addresses for remote locations · Emergency addresses for remote locations > Enable end users to configure their emergency address · Checked 2026-10-01
  34. 34
    Teams emergency addresses assigned to network identifiers for dynamic location must include geo codes; addresses without geo codes cannot be assigned to those identifiers.
    Configure dynamic emergency calling · Configure dynamic emergency calling > Assign emergency addresses · Checked 2026-10-01
  35. 35
    A Windows client with a stateful DHCPv6 address can report a /128 prefix, so Teams LIS computes the full address as the network ID and does not match a /64 LIS subnet entry.
    Configure dynamic emergency calling · Configure Location Information Service > IPv6 subnet matching · Checked 2026-10-01
  36. 36
    When a Teams client queries the Location Information Service, the first matching network element wins in this order: wireless access point, Ethernet switch/port, Ethernet switch, subnet.
    Configure dynamic emergency calling · Configure dynamic emergency calling > Plan for emergency calling, step 2 · Checked 2026-10-01
  37. 37
    Teams LIS subnet matching calculates a network ID from the client IP and client-reported prefix length, and that network ID must equal a subnet configured in LIS (for example 10.10.10.150/25 yields 10.10.10.128).
    Configure dynamic emergency calling · Configure dynamic emergency calling > Configure network settings, Note on LIS subnets · Checked 2026-10-01
  38. 38
    Teams uses this location precedence for an emergency call: admin-defined LIS dynamic address; user-confirmed or edited address tied to the current network; OS-suggested address; user-entered address without service resolution; admin static address on the user's number.
    Emergency addresses for remote locations · Emergency addresses for remote locations > Location precedence · Checked 2026-10-01
  39. 39
    The Teams client sends its location request with network connectivity information at startup, periodically afterwards, and when its network connection changes.
    Configure dynamic emergency calling · Configure dynamic emergency calling > Plan for emergency calling, step 2 · Checked 2026-10-01
  40. 40
    Microsoft states some network settings changes, such as a new address or network identifier, can take up to four hours to propagate to Teams clients.
    Configure dynamic emergency calling · Configure dynamic emergency calling > Configure network settings · Checked 2026-10-01
  41. 41
    A Teams emergency address obtained from the operating system without user confirmation is screened before transfer to the PSAP, while the same address confirmed by the user routes directly to the PSAP.
    Emergency addresses for remote locations · Emergency addresses for remote locations > Emergency address classification and routing (table rows 2 and 3) · Checked 2026-10-01
  42. 42
    Microsoft warns that a successful Teams network-site match (which delivers emergency policies) does not confirm the client obtained an emergency address from LIS.
    Configure dynamic emergency calling · Configure Location Information Service > IPv6 subnet matching, Important box · Checked 2026-10-01
  43. 43
    When a Teams emergency calling policy is assigned to both a network site and a user and the user is at that site, the site policy overrides the user policy.
    Configure dynamic emergency calling · Configure dynamic emergency calling > Enable users and sites, last paragraph · Checked 2026-10-01
  44. 44
    Subnets defined for Teams network sites must also be defined separately in the Location Information Service to render dynamic locations.
    Configure dynamic emergency calling · Configure Location Information Service > Using PowerShell, Important box · Checked 2026-10-01
  45. 45
    In the US, Teams emergency calls that use only the address statically assigned to a user or number, or that carry no address, are screened and then transferred to the PSAP rather than routed directly.
    Emergency addresses for remote locations · Emergency addresses for remote locations > Emergency address classification and routing (table rows 'statically assigned to the user/number' and 'Null') · Checked 2026-10-01
  46. 46
    Teams attempts IP-based dynamic policy or location lookup only when the client's external IP matches a tenant trusted IP address, but switch/port (LLDP) and BSSID lookups are made regardless of trusted IP match.
    Configure dynamic emergency calling · Configure dynamic emergency calling > Configure network settings (paragraph on trusted IP addresses and following Note) · Checked 2026-10-01
  47. 47
    Dynamic emergency calling, including security desk notification, is not supported on the Teams web client; Microsoft suggests a calling policy with Web PSTN calling turned off for those users.
    Configure dynamic emergency calling · Configure dynamic emergency calling > Supported clients, second Note · Checked 2026-10-01
  48. 48
    The Teams work-from-home emergency address experience is for Teams desktop on Windows and Mac; Teams phones do not support it and Teams mobile supports automatic detection but not user-entered addresses.
    Emergency addresses for remote locations · Emergency addresses for remote locations > Notes and restrictions · Checked 2026-10-01
  49. 49
    Subnet-based locations work on all Teams clients, but Wi-Fi-based locations are supported on all Teams clients except Teams phones.
    Configure dynamic emergency calling · Configure dynamic emergency calling > Supported clients, first Note · Checked 2026-10-01
  50. 50
    Cisco advises placing 933 test calls before enabling full 911 routing for a Webex Calling location with RedSky; the 933 call reaches an IVR that announces the caller ID and currently known address for the device.
    Enhanced Emergency Calling for Webex Calling · Enhanced emergency calling for Webex Calling > testing with 933 · Checked 2026-10-01
  51. 51
    The Webex App desktop client reports BSSID, IP address and upstream default gateway MAC for RedSky location, and ignores VPN and virtual network interfaces.
    Enhanced Emergency Calling for Webex Calling · Enhanced emergency calling for Webex Calling > network discovery for Webex App · Checked 2026-10-01
  52. 52
    Off-premises, the Webex App prompts the user for a dispatch address only when it connects from an off-premises network it has not seen before, and reuses the earlier address on a known network.
    Enhanced Emergency Calling for Webex Calling · Enhanced emergency calling for Webex Calling > nomadic E911 / off-premises users · Checked 2026-10-01
  53. 53
    Webex Calling emergency callback number options are the user's own number, the location default ECBN, or another assigned number in the location such as another user, workspace or virtual line.
    Emergency Callback Number (ECBN) in Control Hub · Emergency callback number in Webex Calling > configuration options · Checked 2026-10-01
  54. 54
    Webex Calling ELIN expiry is set per location between 10 and 1440 minutes with a default of 60, and an ELIN with an active unexpired assignment cannot be modified, deleted or moved.
    Configure ELIN for Webex Calling · Configure ELIN for Webex Calling > location-level settings and limitations · Checked 2026-10-01
  55. 55
    In Webex Calling, if no ELIN is available for an emergency call the system uses the configured ECBN of the user, workspace or location.
    Configure ELIN for Webex Calling · Configure ELIN for Webex Calling > ELIN and ECBN relationship · Checked 2026-10-01
  56. 56
    For HELD-capable Cisco MPP phones on Webex Calling with RedSky, location is found by matching the upstream LLDP switch, WAP BSSID, IP address or MAC addresses against the RedSky network map.
    Enhanced Emergency Calling for Webex Calling · Enhanced emergency calling for Webex Calling > network discovery for HELD-capable devices · Checked 2026-10-01
  57. 57
    If RedSky cannot determine any location for a Webex Calling emergency caller, it routes the call to a relay center where agents ask the caller for their location.
    Enhanced Emergency Calling for Webex Calling · Enhanced emergency calling for Webex Calling > no location found behaviour · Checked 2026-10-01
  58. 58
    For Webex Calling devices that are not HELD-capable, RedSky determines location from the caller ID asserted in the test or emergency call.
    Enhanced Emergency Calling for Webex Calling · Enhanced emergency calling for Webex Calling > fixed (non-HELD) device location · Checked 2026-10-01
  59. 59
    For Zoom Phone BYOC numbers whose emergency calls route via the BYOC carrier, the address reported to the PSAP is based on the BYOC carrier's records.
    Routing emergency calls · Routing emergency calls > BYOC section · Checked 2026-10-01
  60. 60
    With Zoom Phone nomadic emergency services, the client prompts the user to confirm or update their emergency address when it detects a network change (IP or MAC address) the user has not reported before, or to add one if no location matches.
    Nomadic emergency services process · Nomadic emergency services process > prompt on network change · Checked 2026-10-01

Documents

tier 1 standards and regulators

47 CFR 9.11 E911 service (interconnected VoIP), 2024 annual edition

U.S. Government Publishing Office (govinfo) · 2024-10-01 · accessed 2026-10-01

tier 1 standards and regulators

47 CFR 9.16 General obligations for 911 dialing, notification, and location (MLTS), 2024 annual edition

U.S. Government Publishing Office (govinfo) · 2024-10-01 · accessed 2026-10-01

tier 1 standards and regulators

47 CFR 9.3 Definitions (Code of Federal Regulations, 2024 annual edition)

U.S. Government Publishing Office (govinfo) · 2024-10-01 · accessed 2026-10-01

tier 2 current vendor documentation

Cisco Emergency Responder Administration Guide, Release 15 and SUs - Troubleshoot Cisco Emergency Responder

Cisco Systems · accessed 2026-10-01

tier 2 current vendor documentation

Configure dynamic emergency calling

Microsoft · 2026-06-15 · accessed 2026-09-21

tier 2 current vendor documentation

Configure ELIN for Webex Calling

Cisco Systems, Inc. (help.webex.com) · 2026-05-06 · accessed 2026-09-16

tier 2 current vendor documentation

Considerations for Direct Routing

Microsoft · 2026-09-10 · accessed 2026-09-24

tier 2 current vendor documentation

E911 for Static VoIP integration & testing guide

Bandwidth · 2026-06-09 · accessed 2026-09-25

tier 2 current vendor documentation

Emergency addresses for remote locations

Microsoft · 2025-04-25 · accessed 2026-09-24

tier 2 current vendor documentation

Emergency Callback Number (ECBN) in Control Hub

Cisco Systems, Inc. (help.webex.com) · 2025-04-01 · accessed 2026-09-16

tier 2 current vendor documentation

Enhanced Emergency Calling for Webex Calling

Cisco Systems, Inc. (Webex Help Center) · 2026-08-21 · accessed 2026-09-16

tier 2 current vendor documentation

Field Notice: FN74155 - Cisco Emergency Responder Emergency Location Identification Number Lookup (ELIN) Fails When Making an Emergency Call - Software Upgrade Recommended

Cisco Systems · 2024-05-31 · accessed 2026-10-01

tier 2 current vendor documentation

Nomadic emergency services process

Zoom · accessed 2026-09-30

tier 2 current vendor documentation

Plan and manage emergency calling

Microsoft · 2026-03-23 · accessed 2026-09-16

tier 2 current vendor documentation

Routing emergency calls

Zoom Communications · accessed 2026-09-24

Cite this page

APA

WarmTransfer. (2026, October 1). Troubleshooting 911 calls that route with the wrong location. WarmTransfer. https://warmtransfer.net/knowledge/e911-routing-failures

BibTeX

@misc{warmtransfer-e911-routing-failures,
  title  = {Troubleshooting 911 calls that route with the wrong location},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/e911-routing-failures},
  note   = {Verified 2026-10-01}
}