Microsoft 365 Outage History

Microsoft 365 users experienced issues accessing web-based services when using Google Chrome Version 147, with problems including missing UI elements, failed page loads in the admin center, and inability to open Excel/PowerPoint files through web pages. The issue was isolated to Chrome browsers, while Microsoft Edge and other browsers remained unaffected. Microsoft resolved the incident by updating authentication components across service endpoints, with users needing to refresh their browser pages to experience relief.

An authentication component misconfiguration disrupted the Autodiscover flow for Exchange on-premises connections, preventing some users from accessing email messages through Outlook Mobile for 71.9 hours starting April 10, 2026. Microsoft identified the root cause and was developing a fix to correct the misconfiguration that was blocking Outlook Mobile from automatically establishing access for affected users. The incident had minor status and impacted users attempting to connect to Exchange on-premises environments through the mobile application.

Microsoft 365 services including Teams and Outlook experienced disruptions due to a network-level issue caused by an external service dependency, affecting users in the US, Netherlands, UK, and Canada. Users reported being unable to access email and encountering login problems with Outlook requiring repeated authentication. Microsoft identified and corrected the network disruption, with services recovering within approximately one hour, though some users experienced brief email delivery delays during the recovery process.

A recent code deployment caused a small subset of Microsoft 365 administrators in North America and Brazil to be unable to access the Microsoft 365 admin center for 4.6 hours. Microsoft identified the problematic deployment and resolved the issue by reverting the changes across their infrastructure. The incident was triggered by user reports of access issues that exceeded normal alerting thresholds.

Some Microsoft 365 users were unable to access the Microsoft 365 web sign-in page and Microsoft 365 Copilot web sign-in page due to service infrastructure not processing traffic efficiently. The issue affected users served through specific infrastructure components, while application-based Copilot services remained accessible. Microsoft implemented configuration changes to address the inefficient traffic processing, with partial recovery observed after 5.3 hours.

Microsoft 365 administrators in the Central US region experienced inability to access or delays when accessing the Microsoft 365 admin center for 3.1 hours due to infrastructure in the Central US datacenter entering a degraded state. Users reported login failures and "service unavailable" messages when attempting to access the admin portal. Microsoft resolved the issue by rerouting traffic away from the affected systems after initial infrastructure restarts proved insufficient.

Microsoft 365 users experienced intermittent issues accessing their Exchange Online mailboxes through Outlook mobile apps and the new Outlook for Mac desktop client over a 33-hour period. The incident was caused by problems with the Notification Broker service in the Exchange Online infrastructure. Microsoft resolved the issue by restarting the Notification Broker service across affected infrastructure and implementing code changes to address contributing factors.

Microsoft 365 Copilot Chat experienced a 15.7-hour outage where users' queries failed with "Sorry, something went wrong. Service unavailable. Please try again." error messages, caused by a configuration service falling below optimal operating thresholds. Microsoft resolved the issue by manually restarting service instances across all affected regions after initial capacity and traffic adjustments proved insufficient for full remediation.

Microsoft 365 users experienced issues accessing archived email messages in Outlook on the web, receiving "Your message cannot be displayed right now" error messages. The problem was caused by a code issue where requests were incorrectly trying to find primary mailboxes instead of archive mailboxes when the two were located on different machines. Microsoft resolved the issue by implementing a code fix that was deployed across all affected infrastructure over approximately three weeks.

Some Microsoft 365 users experienced errors when attempting to create shared mailboxes in Exchange Online, with the service hanging after two-factor authentication and connection issues preventing access to email functions. Users reported inability to load new emails in Outlook and problems connecting to M365 services despite having internet connectivity. Microsoft provided a workaround allowing users to create regular mailboxes and convert them to shared mailboxes while investigating the root cause through HAR log analysis.