Microsoft has traced the global outage affecting Teams, Outlook, and Copilot to a large number of servers becoming unexpectedly unavailable. The company said it is aggressively pursuing fixes and has managed to bring a subset of servers back online.
Widespread Impact Across Industries
The outage has been ongoing for several hours, hitting multiple Microsoft 365 platforms. Outlook emails, Teams messaging, and the Copilot AI assistant are all affected, with industries ranging from health services and hospitals to AI providers and cybersecurity firms reporting disruptions.
In the UK, more than 3,000 users reported issues on outage tracker Downdetector shortly after 6pm, with most struggling to log in to their accounts. In the US, almost 130,000 people have been affected. Reports have declined since that peak, but many users still cannot send or receive emails, while others are unable to load their inboxes.
Cause and Recovery Efforts
Microsoft explained that while no recent changes have been identified that correlate with the start of the impact, its investigation indicates the failed health checks may originate from a specific component on the affected servers responsible for processing them. The company is deploying a targeted change to bypass this component on a subset of servers to validate whether it restores availability, and it has taken steps to prevent additional servers from being removed from service.
Microsoft is also investigating why affected servers are experiencing elevated processor usage while handling requests. At around 2am UK time, the company reported positive results with its efforts to restart affected infrastructure, but less than 30 minutes later it noted it was applying infrastructure capacity improvements where possible to help support traffic in regions coming online.
Affected Services and Next Steps
The list of services currently down has grown significantly. Features that interact with Exchange Online and email services are impacted, including Exchange Online, Microsoft 365 admin center, Microsoft 365 apps, Microsoft 365 Apps Admin Center, Microsoft 365 Education, Microsoft Copilot 365, Microsoft Defender for Office 365, Microsoft Defender XDR, Microsoft Fabric, Microsoft Graph, Microsoft Intune, Microsoft Planner, Microsoft Purview, Microsoft Teams, Microsoft To Do, Power BI, SharePoint Online, Universal Print, and Windows 365.
Microsoft says some elements of services that do not rely on interactions with Exchange Online remain functional. The company continues to monitor the results of changes applied so it can identify strategic actions to improve service health across all affected regions.
