December 07, 1:48pm

Title: Users may be intermittently unable to join group calls in Microsoft Teams from multiple devices
User Impact: Users may be intermittently unable to join group calls in Microsoft Teams from multiple devices.
More info: As an example of impact, a user can connect through the desktop client. However, when the user attempts to connect on a separate connection method such as a mobile device, this may intermittently fail. Users can circumvent this issue by connecting through a Public Switched Telephone Network (PSTN) or only leveraging a single device.
Current status: We're investigating a potential issue and checking for impact to your organization. We'll provide an update within 30 minutes.
Scope of impact: Your organization is affected by this event, and any user attempting to join a group call in Microsoft Teams from multiple devices is affected.

December 07, 2:29pm

More info: Our investigation has determined that a recent update to the group calling API intended to streamline endpoint communication processes caused a compatibility issue, resulting in impact. We've developed and validated a fix and we're aiming to have a deployment timeline by our next update.
Current status: Our investigation has determined that a recent update to the group calling API intended to streamline the endpoint transfer process contained a compatibility error, resulting in impact. We've developed and validated a fix which we believe will resolve this impact, and we're aiming to have a deployment timeline in our next update.
Scope of impact: Your organization is affected by this event, and any user attempting to join a group call in Microsoft Teams from multiple devices is affected.
Root cause: A recent update to the group calling API intended to streamline endpoint communication processes caused a compatibility issue, resulting in intermittent endpoint transfer failures.
Next update by: Tuesday, December 7, 2021, at 10:30 PM UTC

December 07, 3:10pm

More info: As an example of impact, a user can connect through the desktop client. However, when the user attempts to connect on a separate connection method such as a mobile device, this may intermittently fail. Users can circumvent this issue by connecting through a Public Switched Telephone Network (PSTN) or only leveraging a single device.
Current status: We've begun deployment of the fix to the affected environment. We anticipate the deployment will complete on Friday, November 10, 2021, after which we'll monitor to ensure impact is remediated. Some users may begin to experience relief as the fix progresses.
Scope of impact: Your organization is affected by this event, and any user attempting to join a group call in Microsoft Teams from multiple devices is affected.
Estimated time to resolve: We anticipate deployment of the fix to complete on Friday, November 10, 2021.
Root cause: A recent update to the group calling API intended to streamline endpoint communication processes caused a compatibility issue, resulting in intermittent endpoint transfer failures.
Next update by: Friday, December 10, 2021, at 8:00 PM UTC