Microsoft 365 Alert – Service Degradation – Microsoft Teams – Users are seeing Microsoft Teams messaging delays and problems with other service functions – RESOLVED

19/12/2025 14:50:00 PM

NHSmail Reference: INC46710127

Microsoft Reference: TM1200517

Issue Status: RESOLVED

Issue Description: Users may have seen Microsoft Teams messaging delays and problems with other service functions.

More info: Users may have seen delays with the following actions within any Microsoft Teams client:
– Loading, creating, and editing chats and channels.
– Sending and editing messages.
– Loading images in chats and channels.
– Initiating and transferring calls.
– Viewing call history.

Final Update: 22/12/2025 09:55:00 AM – Microsoft has clarified the affected scenarios and enumerated them in the more info section above. They have continued to observe persistent recovery without any manual intervention required, and they have received confirmation from some previously affected users that this issue is no longer occurring.

Scope of impact: Any users served through an affected portion of Microsoft Teams service infrastructure may have seen delays completing the actions identified in the more info section of this communication.

Root Cause: A portion of Microsoft Teams infrastructure became imbalanced and wasn’t processing traffic as efficiently as expected

Next steps: Microsoft are continuing a concerted analysis of the affected infrastructure to identify any trending traffic processing issues necessitating refinement so they can avoid a reoccurrence of this issue.