Microsoft investigates widespread Outlook and 365 service outage

Microsoft said it is investigating a widespread outage that disrupted Outlook email and other services on its 365 platform. The company posted on social media that users in the United States and other regions reported problems accessing Exchange Online mailboxes and connecting to services such as Teams, Azure, OneDrive and Copilot.

"We’re continuing to pursue all available pathways to restore service, as our actions taken thus far have not provided the anticipated relief," the company wrote.

"Workers are fully isolating a portion of our service infrastructure, restarting the affected components, and gradually reintroducing traffic to confirm our services remain stable. We’re also analyzing traffic patterns across our entire service infrastructure and evaluating whether isolating traffic within each region may allow affected regions to recover independently."

Microsoft added that a core process on the affected servers was becoming overwhelmed, causing the servers to stop responding and contributing to capacity loss. It said a portion of infrastructure was experiencing elevated load across multiple regions, which likely contributed to the connectivity errors.

The outage also impacted media companies and other enterprises that rely on Microsoft 365 for business communications. No definitive cause had been identified at the time of reporting. Shares of Microsoft closed slightly higher on the day, ending at $523.