A widespread outage at Microsoft on Thursday affected numerous services, including the email service Outlook. Users were at times unable to send or receive messages and could not load their inboxes. The company said it is investigating the disruption and working urgently to reduce its impact.
According to the platform Downdetector, around 130,000 outage reports for Outlook were received shortly after 1 p.m. Eastern Time. The number of reports fell significantly from this peak afterward, but the problems persisted. In addition, thousands of users reported difficulties with Teams, Copilot and Microsoft 365.
Microsoft essentially attributes the outage to access to mailboxes in Exchange Online in North and South America. Part of the infrastructure was exposed to increased load, which likely intensified the connection errors. Servers became unreachable after failing automated health checks.
According to the company, it is testing a fix as well as an alternative method for the health checks. It said it is pursuing every avenue to reduce the impact. Problems with Teams in North America were initially resolved during the day, but some users subsequently continued to report connection issues.
It remains unclear what exactly caused the servers' health checks to fail. It is also unknown when the service will be fully available again to all users.
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