Microsoft 365 outage disrupts Outlook email worldwide

A worldwide Microsoft 365 outage disrupted email for millions of users on Monday evening, affecting both business customers and private Outlook users. Microsoft confirmed major problems with logins and with sending and receiving messages on its official status pages.

Users also reported that mailboxes no longer synchronized and that the application froze. The company said the problem originated in the cloud infrastructure supporting Exchange Online. An error in a central authentication and connection component prevented normal access to mail servers.

Microsoft identified the incident internally as EX1464935 and said its technicians had begun countermeasures. They were gradually deploying an update to affected servers to restore service. The company did not initially say when email would be fully available worldwide without restrictions.

Reports on outage-monitoring platforms such as Downdetector rose into the tens of thousands within a short time. IT experts advised users not to change local computer settings or reinstall the software because the problem was on the server side. They also warned users not to repeatedly resend messages left in outboxes, as this could lead to duplicate deliveries once service returned.