On Friday, Microsoft apologized for the Microsoft 365 outage, which disrupted access to Outlook email and other services for thousands of users, saying the firm is currently seeing broad recovery and stabilization across the affected services.
“We are deeply sorry for the disruption this incident has caused our customers and partners. We know the trust they place in our services and take that responsibility extremely seriously,”
This announcement was the first explanation for the cause of the failure. It is a technical issue, the company says — not a cyber incident nor something associated with artificial intelligence or agents. There was a problem during an earlier network capacity upgrade, but it only became obvious after the recent network change.
The company said it has resolved the issue and is currently bringing back service to the customers and regions that are still affected.
The return of the service was gradual, given the high demand. Services were returned gradually, checking stability after each step of returning the service. This approach was more time-consuming, the firm says, but it helped to make sure that the service would stay up.
A full post-incident report will be released once the company’s review is complete.
How the outage occurred
The outage started on Thursday when users in the Americas could not reach their Exchange Online mailbox via Outlook on the web, Messaging API, Exchange ActiveSync and REST API. Microsoft logged the problem as incident EX1550543 and later opened incident MO1550821 for Microsoft 365 connectivity problems.
There were nearly 130,000 reports on Downdetector about the issue with Outlook at its maximum level, and the problem affected not only emails but also Teams, SharePoint Online, Microsoft Copilot and Microsoft Defender XDR. On Friday, the firm stated that it has completed all necessary actions for recovery of the affected parts of Asia Pacific infrastructure and mailbox access improvement, though service remained variable for hours afterward.
Also Read: Update: Microsoft 365 Recovery Progressing, Microsoft Says