Story perspectives
Microsoft restores Outlook after multi-day auth misconfiguration outage
9/1/2026
1 of 1
Story summary
- Microsoft is addressing a multi-day outage that disrupted Outlook and other Microsoft 365 services.
- The company traced the problem to a core authentication configuration mis-setup that blocked component deployment.
- Microsoft reverted a recent infrastructure update after testing mitigations to restore the affected components.
- The outage began Monday, with mail flow improving by 10 p.m. ET.
- Full service remained unavailable on Tuesday.
