Microsoft 365 Alert – Service Degradation – Exchange Online – Users may be unable to access the My Templates and Viva Insights add-ins in Exchange Online – ONGOING

10/11/2025 09:38:00 AM

NHSmail Reference: INC46678913

Microsoft Reference: EX1183224

Issue Status: ONGOING

Issue Description: Users may be unable to access the My Templates and Viva Insights add-ins in Exchange Online.

Current Update: 11/12/2025 08:46:00 AM – Microsoft are continuing to analyze the information in order to better understand the root cause, they can confirm that impact is specific to a select few affected. They are working to understand how many users are impacted and expect to have a better understanding by their next scheduled update.

Scope of impact: The problem impacts some users trying to access the My Templates and Viva Insights Outlook add-ins in Exchange Online. This section may be updated as our investigation progresses.

Root cause: A recent change to the Admin API is causing a mismatch in the data format of users’ mailbox cache, and is resulting in the missing Outlook add-ins.

Next update by: Monday, December 15, 2025, at 3:30 PM UTC