Microsoft 365 Outage Ends After 24-Plus Hours, Cause Was Network Upgrade
Microsoft 365 is working again after a global outage that knocked out Outlook, Teams and other Microsoft apps for more than 24 hours, starting Thursday, Microsoft said on Saturday, according to Cointelegraph. The company said it had “restored service to the remaining impacted customers and regions” and pointed administrators to incident MO1550821 in the Microsoft 365 admin center.
Microsoft also repeated that a cyberattack did not cause the disruption.
What stopped working
The trouble hit Exchange Online, the service that hosts Microsoft 365 mailboxes, and features connected to Outlook, Teams and Microsoft Copilot. Users could not reliably reach their email. Government agencies in Japan, Singapore and the United States reported email problems, Cointelegraph reported.
Links between Microsoft 365 and outside AI assistants broke as well. OpenAI said the Microsoft 365 connector in ChatGPT is running normally again. Anthropic marked its own incident, covering its Microsoft 365 connector and Claude for Outlook, as resolved.
Microsoft blames a network capacity upgrade
On Friday, Microsoft said the outage traced back to a problem introduced during an earlier network capacity upgrade, which surfaced after a more recent change to its network. “This was a technical issue not related to cyber or AI/agents,” the company said.
Microsoft said it fixed the underlying problem and brought services back in stages, confirming each stage was stable before moving to the next. That staged approach is why some customers and regions got service back sooner than others.
What this means for Microsoft 365 users
Microsoft considers the incident closed for all customers and regions. If Outlook or Teams still misbehaves on your device, the simple checks apply: look at the Microsoft 365 service status, update the app, and sign out and back in. IT administrators can follow incident MO1550821 in the admin center for Microsoft’s official notes.
People who connect ChatGPT or Claude to their Microsoft 365 mail and calendar should find those connectors working again, according to OpenAI and Anthropic.
What happens next
Microsoft apologized for the disruption. It said it will publish a full post-incident report once its review is finished. The company has not given a date for that report.
Source: Cointelegraph