Microsoft 365 Alert – Service Degradation – Exchange Online – Some users may be unable to use Microsoft Outlook Classic while the Microsoft Teams Meeting Add-in is enabled- ONGOING

Announcements Shagufta Naaz

17/03/2026 09:14:00 AM

NHSmail Reference: INC46775188

Microsoft Reference: EX1254044

Issue Status: ONGOING

Issue Description: Some users may be unable to use Microsoft Outlook Classic while the Microsoft Teams Meeting Add-in is enabled.

More info: If Teams Meeting Add-in is disabled then Outlook Classic functions as normal.

As a workaround, users can also perform an Online Repair of Office or update Outlook to the latest version to resolve the issue.

Current Update: 29/04/2026 09:00:00 AM –Microsoft has experienced an unexpected delay to deploying the fix and will provide an update once the deployment is completed.

Scope of impact: Users attempting to use Microsoft Outlook Classic while the Microsoft Teams Meeting Add-in and previous Outlook build version is enabled may be impacted.

Root cause: A previous Outlook build version that is enabled is causing impact to occur.

Next update by: Tuesday, May 5, 2026, at 11:30 AM UTC