Microsoft 365 outage still disrupting Outlook, Teams and Copilot
November 12: SecurityWeek says Microsoft is testing a health-check workaround, investigating high processor use, and still lists both incidents as degradations, with no evidence of malicious activity.
Microsoft has not restored Microsoft 365; it is testing a health-check workaround after servers went unavailable.
Microsoft has not restored service after a November 12, 2026 Microsoft 365 outage blocking Exchange Online, Teams, SharePoint Online, Microsoft 365 Copilot, and Defender XDR. Advisory MO1550821 began at 1:26 p.m. ET; Exchange Online is also tracked as EX1550543. WIRED and Hacker News describe impact mainly in the Americas, while BleepingComputer says any region may be affected and Security Affairs says Microsoft later warned of worldwide impact. Microsoft first cited elevated load, then said servers failed health checks or became unavailable and strained remaining capacity, not increased traffic. It paused deployments, shifted traffic, and is restarting servers while testing a workaround that bypasses failed health-check processing. SecurityWeek says both incidents were still service degradations just before 3 p.m. ET, with no evidence of malicious activity.
- MO1550821 began at 1:26 p.m. ET; Exchange Online is EX1550543.
- Earlier Teams incident TM1550488 ran 9:45–10:53 a.m. ET and was resolved.
- Microsoft is testing a bypass of failed automated health checks and probing high processor use.
- Security Affairs cites more than 97,000 Downdetector Outlook reports.
- OpenAI and Anthropic reported Microsoft 365 connector failures, according to Security Affairs.
- Some Google Workspace users could not reach mail through Outlook clients.
Timeline
dated events in the reporting · oldest first- Nov 12, 2026Separate Americas Teams incident TM1550488 begins · BleepingComputer
- Nov 12, 2026Teams incident TM1550488 resolved · Security Affairs
- Nov 12, 2026Microsoft 365 advisory MO1550821 begins at 1:26 p.m. ET · BleepingComputer
- Nov 12, 2026Both tracked incidents still listed as service degradations · SecurityWeek
What each outlet adds
beyond the shared facts- Hacker NewsCites EX1550543 and a status page returning 502.
- BleepingComputerSays users in any region may be affected; earlier Teams incident unlinked.
- Security AffairsDowndetector counts and OpenAI and Anthropic connector failures.
- SecurityWeekHealth-check workaround, high CPU, and Google Workspace mail impact.
- WIREDReports no indication of a cyberattack and details mitigation steps.
Coverage
oldest first · one row per article · UTC- · 6h ago
Hacker News · securityFirst report
Exchange Online mailbox access degraded for Microsoft 365 in the Americas
Microsoft is investigating connectivity errors on part of Exchange Online under incident EX1550543; the status site is also failing to load.
- · 5h ago
WIRED · Security
Microsoft 365 outage blocks Outlook and Exchange Online in the Americas
Microsoft says servers failed health checks and went offline, with no indication of a cyberattack.
- · 4h ago
BleepingComputer
Microsoft 365 outage disrupts Outlook, Teams and Copilot worldwide
Advisory MO1550821 began at 1:26 PM ET after servers became unavailable; Microsoft has not restored service.
- · 4h ago
Security Affairs
Microsoft 365 outage hits Outlook, Teams, Copilot and AI connectors
Downdetector logged more than 97,000 Outlook reports; Microsoft later blamed unexpectedly unavailable servers, not extra traffic.
- · 4h ago
SecurityWeek
Microsoft 365 outage disrupts Outlook, Exchange Online and Teams
Microsoft blamed unavailable servers, not higher traffic, and has reported no evidence of a cyberattack.