Microsoft 365 Alert – Service Degradation – Exchange Online – Users may be unable to access the My Templates add-in in Outlook – RESOLVED

23/03/2026 11:58:00 AM

NHSmail Reference: INC46779675

Microsoft Reference: EX1255397

Issue Status: RESOLVED

Issue Description: Some users may be unable to access the My Templates add-in in Outlook

More info: This issue impacts both the Outlook desktop client and Outlook on the web. Some affected users find that the “My Templates” icon is missing from the Outlook ribbon and others may be unable to find templates in the AppData Microsoft Templates location, even though templates are known to exist and may still be being used by other (non-impacted) users.

Final Update: 01/04/2026 08:55:00 AM–Microsoft has identified that a recent Exchange Web Services (EWS) deprecation update and an Exchange Online authentication change prevented users from accessing default add-ins in Outlook. To remediate this issue, they rolled back both offending changes and verified through service monitoring that this action successfully resolved the impact. Admins that have disabled EWS may continue to experience this issue and we recommend that admins re-enable EWS at this time. For additional guidance on managing Exchange Web Services, please refer to the following:
https://learn.microsoft.com/en-us/exchange/client-developer/exchange-web-services/how-to-control-access-to-ews-in-exchange

Scope of impact: Some users attempting to access or use the My Templates add-in within Outlook may be impacted. This information may be updated as our investigation continues.

Next steps: Microsoft has reviewing how the impacting changes prevented users from accessing default add-ins so we can avoid similar issues in the future, as EWS is slated to be deprecated by October 2026.