Microsoft 365 Alert – Service Degradation – Exchange Online – Some users may be unable to access their Exchange Online email using Outlook for Mac – RESOLVED

Announcements Arpan Das

22/10/2025 09:13:00 AM

NHSmail Reference: INC46662395

Microsoft Reference: EX1176994

Issue Status: RESOLVED

Issue Description: Users may have been unable to access their Exchange Online email using Outlook for Mac.

More info: Some users’ Mac devices may have been quarantined, which prohibited impacted users from accessing their email in Outlook for Mac.

Final Update: 22/10/2025 09:03:00 AM – Microsoft have confirmed with reporting users that the issue is now resolved. If they are still experiencing impact, close, then reopen Outlook and wait ten seconds. If they receive an error message that says, “This account has been blocked on this device by your administrator,” please repeat the steps above until you no longer receive the error message.

Root cause: The latest build release contained a code issue which caused the Exchange ActiveSync policy to block the Outlook for Mac client, resulting in the impact.

Next Steps: Microsoft will provide a preliminary Post-Incident Report within two business days and a final Post-Incident Report within five business days.