Microsoft 365 Outage Slams Businesses as Exchange Online Falters

Microsoft has zeroed in on the culprit: overloaded infrastructure. The company said a portion of its systems is seeing "elevated load across multiple regions," which it believes is fueling the connectivity errors. Crews are restarting and repairing the affected pieces to restore capacity, while also digging into an unexpected spike in one type of service traffic to see if that's piling on. In the meantime, Microsoft says it's weighing redirecting traffic to alternate infrastructure to speed up relief.

The pain is concentrated on Microsoft 365 business and enterprise customers, who lost email access through the Exchange server. Microsoft warned the issue "may affect Microsoft 365 service connectivity for users in any region," even though the earliest complaints came from the Americas. Stand-alone Outlook was deemed operational, and so were Teams and OneDrive.

Microsoft owned up to the mess in a string of social media posts Thursday, saying it was investigating reports of users who couldn't reach Exchange Online mailboxes through multiple connection methods. Media companies were among the businesses across every sector whose work ground to a crawl. Microsoft hasn't said how many customers or users are caught up in the outage.