Outlook on Mac users may be unable to connect to their Exchange Online mailboxes
Incident Report for ITS System Status
Resolved
Microsoft has informed us that the issue has been resolved.

If you are one of the affected users, please check and install the most recent version using
Help > Check for Updates or via the Microsoft AutoUpdate application.

More information: Update Office for Mac
Posted Mar 26, 2024 - 10:33 EDT
Update
As Microsoft continues to monitor the fix deployment, they've assessed that the deployment process is taking longer than originally anticipated.

Updated Scope of Impact:
Users on the legacy Outlook for Mac client that's on version 15.20 and builds 7409.15 or below may be impacted.
Posted Mar 25, 2024 - 08:04 EDT
Identified
Current status: The fix is continuing to deploy to the affected environment. Microsoft is monitoring its progress and anticipates it may be finished saturating by their next scheduled communication update.

Scope of impact: Any user of the legacy Outlook for Mac hosted on the affected infrastructure may be impacted.

Workarounds (if you can't Sign in to your work account with Outlook Mac OS app):

1. Temporarily use Outlook for Web
2. Temporarily switch to the New Outlook app
Posted Mar 21, 2024 - 11:00 EDT
This incident affected: Email Systems (Office 365).