Status Page

O365 - Email/Outlook

2026-04-21	Status	Description
01:33 PM		Title: Users may be unable to access their mailboxes with Outlook on the web and the new Outlook desktop client User impact: Users may have been unable to access their mailboxes with Outlook on the web and the new Outlook desktop client. More info: While we were focused on remediation, users that had access to the classic Outlook desktop or Outlook mobile apps could have used them to circumvent the impact. Final status: We've monitored the affected environment and confirmed that our code regression fix has remediated the impact. Scope of impact: Users located in France and Canada that attempted to access their mailboxes from Outlook on the web and the new Outlook desktop client may have been impacted. Root cause: A subset of control plane service infrastructure that helps monitor and secure multiple Outlook service connections was performing below our manageable service performance thresholds due to a code regression. This issue was preventing users from accessing their mailboxes from Outlook on the web and the new Outlook desktop client. Next steps: - We're reviewing and improving our code update validation procedure to detect and prevent similar issues before they cause impact in the future. This is the final update for the event.