Microsoft is working to restore its cloud services after a major global outage disrupted Outlook, Microsoft Teams and several other Microsoft 365 applications.
The disruption began on November 12 and continued into Friday, November 13, affecting businesses, government organizations and individual users across multiple countries. Although Microsoft has started recovering affected infrastructure, some customers are still experiencing service interruptions.
The outage primarily affects Exchange Online, Microsoft’s cloud-based email service, with problems extending to other products that depend on its email, calendar and contact infrastructure. Outlook users have reported difficulties accessing their mailboxes through desktop, web and mobile applications, while some emails have been delayed or failed to arrive. At the height of the disruption, Downdetector recorded nearly 130,000 reports related to Outlook, highlighting the scale of the incident.
Microsoft Teams has also experienced disruptions, particularly with calendar access, meeting scheduling and certain organization-specific chat features. However, Microsoft says core messaging and online meetings have largely remained functional. SharePoint users can still access files stored directly on the platform, although some features connected to Exchange Online have been affected.
Other impacted services include Microsoft 365 Copilot, Microsoft Defender, Planner, To Do, Intune, Purview and parts of the Microsoft 365 administration infrastructure. Copilot users may encounter problems loading chats or accessing work information, while some security management features and administrative portals may also become unavailable. The disruption has also affected certain Microsoft Graph API requests involving email, calendar and contact information.
According to Microsoft’s investigation, a core process on affected servers responsible for establishing secure connections became overwhelmed, causing the servers to stop processing requests. This resulted in reduced infrastructure capacity and connectivity problems across multiple services. Microsoft has been examining the affected server infrastructure, traffic patterns and configuration changes while working to identify the underlying cause.
The company initially struggled to restore services because some servers became unresponsive again after traffic was redirected to them. Microsoft has since introduced changes to its authentication and routing infrastructure, restarted affected servers and adjusted traffic distribution to improve stability. Engineers are gradually returning repaired infrastructure to service while monitoring its performance.
The recovery process has started showing positive results across several regions. Microsoft has reported improvements in parts of its Asia-Pacific infrastructure, with traffic gradually being restored and mailbox access and delayed email delivery beginning to improve. However, service availability may remain inconsistent for some customers as additional infrastructure is brought back online.
Microsoft is also working through the backlog of delayed emails. According to service updates, the company will continue attempting to deliver affected messages for up to 48 hours, meaning emails sent during the disruption may still arrive as services recover.
The company has said it is not aware of any malicious activity causing the outage. Microsoft has not yet published a complete explanation of the incident and plans to provide further details, including the underlying cause and steps intended to prevent similar disruptions, in a post-incident report once the situation is resolved.
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