Microsoft 365 outage disrupts email at Openreach

Microsoft 365 customers worldwide lost reliable access to email on Thursday 12 November, and Microsoft was still restoring service on the afternoon of Friday 13 November. Openreach said on 13 November that its internal systems, email included, were disrupted.

The fault is in Exchange Online and reaches every Microsoft 365 feature that depends on it. Microsoft’s service status page says users may be unable to open their mailbox through Outlook on the web, the Outlook desktop app or mobile mail, and that delivery may be delayed. Parts of Copilot, SharePoint, Planner and the Defender and Purview security tools are failing with it, and Intune has had intermittent problems. Teams calls, meetings, group chats and channel messages still work. Scheduling a meeting or editing one may fail.

Microsoft began investigating mailbox failures in the Americas on Thursday. It says the wider Microsoft 365 incident began at 18:26 UK time. It first put the problem down to heavy load on part of its infrastructure. It then said a number of servers had unexpectedly become unavailable, which strained those still running, BleepingComputer reported from the company’s status updates. Microsoft paused all deployments, moved traffic away from the affected systems and restarted servers. It has extended its email timeout window to 48 hours to preserve delayed messages.

Openreach said customers and partners may face delays when contacting it “through certain channels”. Its broadband, phone and other connectivity services are unaffected. ISPreview reported that several UK broadband and mobile providers run customer support and email on Microsoft’s services.

By 14:00 on Friday, queues of delayed messages were “significantly reduced and approaching normal levels”, Microsoft said. A full post-incident report, with the root cause, is due once repairs are complete.