The Microsoft 365 outage affects Exchange Online, Teams and Sharepoint

Microsoft is working to resolve a persistent and widespread outage in Microsoft 365 that is impacting multiple services and features, including Exchange Online, Microsoft Teams, and SharePoint Online.

Since this outage began about six hours ago, Downdetector has received thousands of reports, with affected users saying they are also experiencing issues connecting to other services such as OneDrive, Purview, Copilot and Outlook Web and Desktop.

“We are investigating an issue affecting users attempting to access Exchange Online or features in Microsoft Teams Calendar. For more information, see MO941162 in the Admin Center,” the company said when it confirmed the issues 6 hours ago.

“As we continue to resolve the issue, we have added a comprehensive list of affected services and scenarios to the Learn More section.”

In the Admin Center incident report, Microsoft confirmed that the outage prevents customers from accessing Exchange Online through Outlook on the web, the Outlook desktop client, Representational State Transfer (REST), and Exchange ActiveSync (EAS).

The company also says some customers may have issues performing actions in Microsoft Fabric, Microsoft Bookings, and Microsoft Defender for Office365.

While Remond only announced that the outage was caused by a “recent change,” the company has already deployed a solution to the affected infrastructure, restarted affected systems and is monitoring the situation.

“We have begun deploying the fix, which is currently underway in the affected environment. As this progresses, we will begin manual reboots on a subset of machines that are in an unhealthy state,” Microsoft said an hour ago.

“We are monitoring the progress of the fix, which has been deployed to approximately 60% of affected environments. We are continuing our manual restarts on the remaining affected machines.”

The Microsoft 365 Office service health and network health status pages do not currently show any issues with the company’s network health status and availability, ISP availability, and the customer’s network infrastructure.

In July, another global outage crippled several Microsoft 365 and Azure services, including the Admin Center, Intune, Entra, Power BI, and Power Platform services.

A day later, the company admitted that the nine-hour outage was caused by a distributed denial of service (DDoS) attack.

Update November 25, 12:33 EST: According to Microsoft, the provided fix has not yet resulted in a full recovery.

“The patch is 90 percent deployed and telemetry shows service availability is recovering. An estimated time for completion of the fix is ​​not yet available,” Microsoft said.

“Targeted server reboots are underway to address routing service issues, with priority given to customers who are currently in business hours or beginning their business day.”

Update November 25th, 6:25 p.m. EST: Microsoft shared additional information about the root cause of this incident, saying it was caused by “a change that caused an influx of retry requests to be routed through servers, impacting service availability.”

“We noticed a change that resulted in a flood of retry requests being routed through servers, impacting service availability. To address this, we have implemented optimizations to improve the processing capabilities of the infrastructure. These changes have resulted in gradual relief and we are closely monitoring the service to ensure stability,” the company added on its service health portal.

“Our team is actively following up and will initiate additional work if necessary to fully resolve the issue. Thank you for your patience as we work to restore full functionality.”