Microsoft 365 Alert – Service Degradation – Microsoft Teams – Users may be unable to sign into Microsoft Teams Rooms (MTR) on Windows devices – RESOLVED

Announcements Sharmista Mohanta

29/06/2026 09:46:00 AM

NHSmail Reference: INC46863579

Microsoft Reference: TM1406826

Issue Status: RESOLVED

Issue Description: Users may be unable to sign into MTR on Windows devices.

Final Update: 29/06/2026 09:49:00 AM – Microsoft has completed their investigation into the Microsoft Teams Rooms device client logs along with our service metrics and identified a recent service side change related to Microsoft Teams Rooms devices is causing impact. They have reverted the impacting change and are monitoring their telemetry to confirm that this issue is resolved.

Scope of impact: Users attempting to sign into MTR on Windows devices may be impacted by this issue. This section may be updated as our investigation continues.

Root cause: A recent service side change related to Microsoft Teams Rooms devices is causing impact.

Next steps: We continually review our monitoring to reduce detection time and notify customers of issues with external services.