Microsoft 365 Outage History

Microsoft 365 services, specifically Exchange Online and Microsoft Teams, experienced intermittent access issues for users in the United States due to a load balancing problem in the networking infrastructure. The issue occurred when only a subset of recently decommissioned networking infrastructure was reinstated to active service, causing improper traffic routing. Microsoft resolved the incident by manually reinstating the complete networking infrastructure and confirmed positive service health trends through monitoring.

Microsoft 365 experienced a 26.6-hour incident where some users were unable to access Office.com and Microsoft 365 Copilot web sign-in pages due to high traffic volume overwhelming the supporting infrastructure. The Microsoft 365 Copilot web clients recovered after about 4.5 hours through configuration changes and traffic rebalancing, while Office.com access issues persisted longer. Microsoft resolved the incident by applying traffic optimization configurations and monitoring service stability, with users able to work around the issue by using desktop applications or alternative sign-in methods during the outage.

Some Microsoft 365 users were unable to access Office.com and Microsoft 365 Copilot web sign-in pages due to inefficient traffic processing in a section of service infrastructure. The 12.1-hour outage affected web-based access to office.com and various Copilot web clients, though users could still access Copilot through desktop and mobile applications. Microsoft resolved the issue by implementing configuration changes to optimize traffic routing and monitored service telemetry to ensure recovery.

Microsoft 365 Exchange Online experienced a 5.9-hour service incident where some users, particularly in Europe, encountered errors and failures when accessing their mailboxes through multiple connection methods including Outlook on the web, Outlook desktop, Exchange ActiveSync, and other Exchange Online protocols. Microsoft identified a backend issue preventing services from responding as expected, causing mailbox access delays across regions. The issue was resolved through natural recovery with Microsoft monitoring telemetry data to confirm service stability was restored.

Microsoft 365 users experienced an issue where they could not save personalization settings in Microsoft Copilot Chat, encountering a "Something went wrong, and we couldn't save your changes. Try refreshing the page." error message. The root cause was identified as an API that was incorrectly routing to a deprecated version of the Copilot model instead of the current one. Microsoft deployed a fix to route requests to the correct model and monitored its deployment across the affected environment.

A code issue in Microsoft Teams Meeting Add-in version 26043.2016.4478.2773 caused compatibility problems with classic Outlook, resulting in application crashes and launch failures for some users. The incident affected users running classic Outlook with the problematic Teams add-in enabled. Microsoft resolved the issue by recommending users upgrade to the latest Outlook version or perform an Online Repair of Office, while also working on deploying a permanent compatibility fix.

Microsoft 365 users experienced intermittent issues accessing their Exchange Online mailboxes through Outlook mobile apps (Android and iOS) and the new Outlook for Mac desktop client over a 497-hour period. The root cause was identified as a recent update intended to enable new Virtual Account functionality that introduced a routing conflict preventing proper syncing to the Exchange service. Microsoft resolved the issue by disabling the impacting updates and implementing secondary mitigation measures, with telemetry showing significant reduction in errors and continued monitoring to ensure full remediation.

Microsoft 365 services experienced a 3-hour outage affecting users in the North American region, preventing access to the admin center, SharePoint Online, and Microsoft Teams. Users reported inability to access files in Teams, SharePoint sites failing to load, Planner not working, and email issues lasting over 24 hours. Microsoft investigated Content Delivery Network (CDN) configurations and third-party network provider interactions, with some users reporting recovery before the incident was fully resolved.

SharePoint Online admins experienced access issues to the admin center, receiving "Sorry, something went wrong" error messages, and the top navigation suite bar failed to load across SharePoint sites for all users. The issue was initially region-specific to Australia but later expanded globally, lasting over 50 hours. Microsoft resolved the problem by identifying a faulty service update, redeploying a healthy version of the SharePoint Online service, and implementing a configuration change to address caching issues that prevented some users from receiving the initial fix.

Microsoft Copilot Chat web app experienced an outage lasting 1.8 hours, preventing users from accessing or using the service through office.com and m365.cloud.microsoft, with confirmed impact to users in Australia. Users encountered error messages stating "We are sorry, something went wrong" and were unable to log into their accounts. Microsoft investigated the issue by reviewing telemetry data and impact details to determine the scope and resolution.