Outage
Microsoft fixes Exchange sign-ins broken by Windows Server updates
BleepingComputer · By Sergiu Gatlan ·
The Brief
- Microsoft has fixed Outlook sign-in issues on Exchange Server systems.
- The same fix addresses mail delivery problems on those systems.
- The issues appeared after installing the October 2026 Windows Server security updates.
Why it matters
Administrators who installed the October 2026 Windows Server updates on Exchange Server may have seen broken Outlook sign-ins and mail delivery until this fix was applied.
Who’s affected
- Exchange Server administrators
- Windows Server admins who installed the October 2026 security updates
- #exchange-server
- #windows-server
- #outlook
- #microsoft
- #patches
Microsoft has fixed Outlook sign-in and mail delivery issues on Exchange Server systems after installing the October 2026 Windows Server security updates. [...]