User impact: Users may be unable to run Outlook (classic) in online mode and admins may be unable to utilize the EAC.

More info: Some users may receive the following error: “HTTP 503 Service Unavailable.”
Additionally, when attempting to complete operations in the EAC, admins are returned a “503 Service Unavailable” error. This can potentially impact any EAC related operation, including but not limited to mailbox provisioning. Admins who can leverage PowerShell to complete these tasks can do so to avoid this issue.

Current status: We’re continuing our review of the stack logs in parallel with our investigation into the identified connectivity and latency issues in the provisioning handler calls to progress our investigation into the underlying cause of this issue, so we can determine our next steps regarding impact remediation.

Scope of impact: Any user who attempts to start Outlook (classic) in online mode or any admin utilizing the EAC may be impacted by this event.

Start time: Monday, April 14, 2025, at 12:00 AM UTC

Next update by: Friday, April 25, 2025, at 10:00 PM UTC