Microsoft 365 Alert – Service Degradation – Microsoft Copilot (Microsoft 365) – Some users may encounter an error when using the Microsoft 365 Copilot rewrite feature in classic Outlook – RESOLVED

Announcements Shagufta Naaz

12/06/2026 08:56:00 AM

NHSmail Reference: INC46849909

Microsoft Reference: CP1387482

Issue Status: RESOLVED

Issue Description: Some users may encounter an error when using the Microsoft 365 Copilot rewrite feature in classic Outlook.

More info: Copilot rewrite feature functionality works as expected in Outlook on the web and new Outlook.

When affected users select text and use the Copilot rewrite option in classic Outlook, they may encounter the following error message, “Sorry, something went wrong. Copilot is working on it.”

Final Update: 01/07/2026 09:41:00 AM – Microsoft has confirmed that the fix has completed deployment and validated this issue has been remediated with affected users.

Scope of impact: Impact is specific to some users of the Copilot rewrite feature in classic Outlook.

Next Steps: Microsoft are continuing their analysis of provided client captures and of the recent deployment to better understand the underlying cause of impact and prevent similar impact in the future.