Microsoft 365 Outage: Outlook, Teams and Copilot Disrupted for Over 14 Hours as OpenAI and Anthropic Tools Hit

Microsoft 365, Outlook, Teams and several other Microsoft applications stayed disrupted for thousands of users for more than 14 hours on Friday. Many people were left unable to open emails, join meetings or carry out routine work tasks. Microsoft said unexpected server failures were behind the disruption, which also hit Copilot and other services.

The problem spread beyond Microsoft’s own products. OpenAI and Anthropic’s AI tools were affected through their Microsoft 365 connectors, disrupting connections and the way those tools worked.

Downdetector reports of Outlook problems peaked at around 1.30am on Friday, with 138,058 reports. By 4.30am, the figure had fallen to roughly 34,490. In a statement issued at 3.30am, Microsoft said it was working to restore the affected servers, with services recovering gradually as users reconnected.

What Caused the Microsoft Outlook and Microsoft 365 Outage?

Microsoft said its investigation had pointed to a process that establishes secure connections on the affected servers as a key factor. The process became overwhelmed, causing the servers to stop processing requests. The company has posted more than 15 updates on X since the outage was first reported, setting out its efforts to restore services.

In its latest update, Microsoft said it was “scaling up virtual machines” to increase capacity and reduce the load on its systems. It is also trying to repair machines stuck in a faulty state by forcing a sync of recent network changes, which it said could improve availability. Some machines are not syncing as expected, which has slowed recovery. “We’ll continue to monitor the effectiveness of changes applied,” Microsoft said, adding that it would make further adjustments if needed.

Earlier, the company said it was preparing a configuration change to address the issue. The change was being tested on a subset of servers before a wider rollout, alongside restarts of the affected infrastructure. Microsoft was also reversing a recent network configuration change that coincided with the start of the outage, to determine whether it had contributed to the disruption.

Temporary traffic restrictions were introduced in certain locations. Microsoft said it was monitoring the affected servers to check they remained stable while handling fewer connections, before gradually restoring more traffic. It also clarified that the problem was not caused by an overall rise in traffic, but by fewer servers being available to manage it.

“We are aware and investigating reports of users experiencing issues with Microsoft 365 services, primarily issues with Exchange Online,” a Microsoft spokesperson said.

Which Microsoft Services Were Down? Outlook, Teams, Copilot and More

Several services that rely on Exchange Online and email infrastructure were affected, although features that do not depend on those services continued to work.

Exchange Online users had difficulty accessing their mailboxes through Outlook on the web, desktop applications and mobile connections, and email delivery was delayed. In Microsoft 365 apps, users could not access recently used files, while some pages in the Microsoft 365 admin centre failed to load.

Microsoft Copilot was also affected. Users reported problems loading Copilot Chat or receiving responses on web and desktop applications, and its ability to access work data such as emails, calendars and files was disrupted.

Microsoft Teams continued to support core messaging and online meetings largely as normal. However, features dependent on Exchange Online were affected, including calendars, meeting scheduling and creating chats in organisations using Information Barriers.

Other services listed as affected included:

• Microsoft Planner
• Microsoft To Do
• Microsoft Defender
• Microsoft Purview
• Microsoft Graph
• Microsoft Fabric
• Power BI
• SharePoint Online
• Universal Print
• Windows 365

Microsoft 365 Education features, including Assignments, Reading Progress and Speaker Progress, were hit too, and some Microsoft Intune services were also listed among the affected products.

OpenAI and Anthropic AI Tools Affected by Microsoft 365 Connector Problems

The disruption reached third-party services that rely on Microsoft’s infrastructure. OpenAI said it was investigating an issue with Microsoft connectors that could prevent new connections and cause tools to malfunction. Anthropic said it had identified an issue with an upstream provider affecting its Microsoft 365 connector.

Airlines, Governments and Businesses Feel the Impact of the Global Microsoft Outage

The outage disrupted businesses and public services around the world, including India’s aviation sector. IndiGo warned that its email support system was affected and customers might not receive responses, advising those needing urgent help to contact 6E Skai through its website or app. The airline said its other support channels remained operational.

Air India said its flights and customer communication systems were unaffected. It added that it had rerouted email traffic to ensure messages were received and responses sent within 24 hours.

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Government agencies in Australia, Japan and Singapore were also affected, as was the Philippines Supreme Court. Some reported email problems and possible delays in public responses, but authorities said alternative communication channels helped maintain essential operations.

Electric truck maker Workhorse Group rescheduled its third-quarter results announcement from November 12 to November 16, citing business disruptions caused by the global Microsoft outage.

The incident comes weeks after Microsoft reported a disruption to its Azure cloud platform, which affected its productivity software suite and businesses across several industries worldwide.