Microsoft 365 Alert – Service Degradation – Microsoft Copilot (Microsoft 365) – Users’ Copilot for Sales add-in may not appear on Outlook mobile and Outlook for Mac clients – ONGOING

Announcements Shagufta Naaz

17/03/2026 08:47:00 AM

NHSmail Reference: INC46774733

Microsoft Reference: CP1253444

Issue Status: ONGOING

Issue Description: Users’ Copilot for Sales add-in may not appear on Outlook mobile and Outlook for Mac clients.

More info: This event is related to a known issue with Microsoft Office add-ins, as explained in the following public documentation under “ISSUE: Intermittent failure to load or deploy Office Add-ins due to Exchange authentication changes”:

https://learn.microsoft.com/en-us/office/dev/add-ins/resources/resources-office-add-in-known-issues#issue-intermittent-failure-to-load-or-deploy-office-add-ins-due-to-exchange-authentication-changes

Current Update: 16/04/2026 09:06:00 AM– Microsoft are awaiting confirmation from a subset of reporting users that the impact has been resolved while continuing to collect additional diagnostic logs to support the development of a fix for the remaining affected users.

Scope of impact: Some users attempting to view their Copilot for Sales add-in on Outlook mobile and Outlook for Mac clients may be impacted. This section may be updated as our investigation continues.

Root cause: A portion of infrastructure responsible for the functionality of the Copilot for Sales add-in on Outlook mobile and Outlook for Mac clients isn’t processing requests as efficiently as expected and is resulting in impact.

Next update by: Tuesday, April 21, 2026, at 1:30 AM UTC