Microsoft 365 outage hits Exchange, Teams, SharePoint, Copilot and Defender
Original title: Massive Microsoft 365 Outage Impacts Exchange Online, Teams, SharePoint, Copilot, and Defender XDR Users
Servers became unavailable rather than overloaded by traffic, and restored machines later failed again under load.
A Microsoft 365 outage that began on November 12 continued into November 13 as Microsoft restored failing infrastructure. Connectivity problems may affect users in any region, spanning Outlook, Teams, SharePoint, Copilot and Microsoft Defender XDR, though Microsoft has not said every customer is affected. Failed automated health checks and an overwhelmed core process reduced capacity; engineers shifted traffic and tested a wider recovery method. Microsoft describes infrastructure failure, not a confirmed cyberattack, and has not confirmed full restoration or a completion time.
Unconfirmed: Root cause, exact feature restrictions, and whether service is fully restored remain unconfirmed.
- Exchange Online mailbox issues in the Americas are tracked as EX1550543.
- Broader service impact is tracked as incident MO1550821.
- An alternative health check returned some servers, but improvement was not immediate.
- Rollback of recent configuration updates is a recovery option, not a confirmed cause.
- 1.Follow EX1550543 and MO1550821 in the Microsoft 365 admin center.
- 2.Use Microsoft's public service status page if the admin center is unavailable.
- Vendors
- Microsoft
From the original article
3 min read at cybersecuritynews.com
A major Microsoft 365 outage disrupted cloud service access on November 12 and continued into November 13, 2026, as Microsoft worked to restore failing infrastructure. Microsoft confirmed that connectivity problems could affect users in any region, expanding the scope beyond its initial investigation into Exchange Online mailbox access in the Americas. The reported impact spans […]
By Guru Baran · cybersecuritynews.com
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