Some users conferenced into a Microsoft Teams emergency call may not be automatically muted or able to mute themselves

Title: Some users conferenced into a Microsoft Teams emergency call may not be automatically muted or able to mute themselves

User impact: Users conferenced into a Microsoft Teams emergency call may not be automatically muted or able to mute themselves.

More info: Users conferenced into a Microsoft Teams emergency call are also unable to mute themselves and would need to leave the call.

Current status: We've initiated deployment of our code change to address the code mismatch causing users to not be automatically muted as expected or being able to mute themselves in emergency calls. We anticipate deployment to be completed by Monday, October 12, 2026, and we aim to provide updates on our timeline to remediation as deployment progresses.

Scope of impact: Users conferenced into a Microsoft Teams emergency call and attempting to mute their audio are affected by this issue. This section may be updated as the investigation progresses.

Start time: Friday, September 25, 2026, at 8:09 PM UTC

Estimated time to resolve: We anticipate impact to be resolved by Monday, October 12, 2026.

Root cause: A code mismatch in the components utilized when marking a Microsoft Teams emergency call as a multi-party call is causing the code to mute participants to not be enabled as expected.

Next update by: Friday, October 9, 2026, at 11:00 PM UTC

Title: Some users conferenced into a Microsoft Teams E911 call may not be automatically muted or able to mute themselves

User impact: Users conferenced into a Microsoft Teams E911 call may not be automatically muted or able to mute themselves.

More info: Users conferenced into a Microsoft Teams E911 are also unable to mute themselves and would need to leave the call.

Current status: After analyzing correlation and meeting IDs provided by a subset of affected users, we've isolated a code mismatch in the components utilized when marking a Microsoft Teams call as a multi-party call is causing the code to mute participants to not be enabled as expected. We've expanded our communications to all potentially affected tenants and updated the "Title", "User impact" and "Scope of impact" fields of our communications to reflect this change as we begin rolling out a code change to remediate the mismatch.

Scope of impact: Users conferenced into a Microsoft Teams E911 call and attempting to mute their audio are affected by this issue. This section may be updated as the investigation progresses.

Start time: Friday, September 25, 2026, at 8:09 PM UTC

Root cause: A code mismatch in the components utilized when marking a Microsoft Teams call as a multi-party call is causing the code to mute participants to not be enabled as expected.

Next update by: Monday, October 5, 2026, at 11:30 PM UTC

Title: Some users conferenced into a Microsoft Teams E911 call may not be automatically muted or able to mute themselves

User impact: Users conferenced into a Microsoft Teams E911 call may not be automatically muted or able to mute themselves.

Current status: We're analyzing affected meeting and correlation IDs provided by a subset of affected users to further our understanding of the underlying impact scenario and to determine what our next troubleshooting steps should be.

Scope of impact: Users conferenced into a Microsoft Teams E911 call and attempting to mute their audio are affected by this issue. This section may be updated as the investigation progresses.

Title: Some users conferenced into a Microsoft Teams E911 call may not be automatically muted or able to mute themselves

User impact: Users conferenced into a Microsoft Teams E911 call may not be automatically muted or able to mute themselves.

Current status: We're investigating a potential issue with Microsoft Teams and checking for impact to your organization. We'll provide an update within 30 minutes.