Microsoft confirmed a widespread, multi-hour outage on Monday that affected Outlook users, resulting in email delays, authentication issues, and other problems. The company identified the issue as impacting its Exchange Online service, a cloud-hosted platform for business email, calendar, contacts, and tasks. In a post on X, Microsoft stated it had pinpointed an “authentication component” as the source of the problem and was testing a remediation strategy with a portion of the infrastructure to determine if it resolves the issue before a broader rollout.
User reports of the outage began around 11:30 a.m. ET on Monday, with the crowdsourced outage detection website Downdetector recording over 5,000 reports by 2 p.m. ET. Affected users experienced delays and failures in sending or receiving messages, search functionality issues within their mailboxes, authentication errors, and disruptions in various mailbox operations and message delivery workflows. As of 5 p.m. ET on Monday, Microsoft was still working to resolve the problem, and the article was updated following the company’s additional status information. Source