SHD / MC Checker

[serviceDegradation] EX1056704 | Exchange Online | Users may see a 503 error when starting Outlook (classic) in online mode or utilizing the Exchange admin center (EAC)



EX1056704 | Exchange Online | Users may see a 503 error when starting Outlook (classic) in online mode or utilizing the Exchange admin center (EAC)

Status serviceDegradation
Classification advisory
User Impact Users may see a 503 error when starting Outlook (classic) in online mode or utilizing the EAC.
Last Updated 04/25/2025 12:13:46
Start Time 04/02/2025 04:29:00
End Time
Latest Message Title: Users may see a 503 error when starting Outlook (classic) in online mode or utilizing the Exchange admin center (EAC)

User impact: Users may see a 503 error when starting Outlook (classic) in online mode or utilizing the EAC.

Title: Users may see a 503 error when starting Outlook (classic) in online mode or utilizing the Exchange admin center (EAC)

User impact: Users may see a 503 error when starting Outlook (classic) in online mode or utilizing the EAC.

More info: Some users intermittently may be unable to start Outlook (classic) when in working online mode and encounter the following error: “HTTP 503 Service Unavailable.”

Additionally, when attempting to complete operations in the Exchange admin center (EAC), admins are returned a “503 Service Unavailable” error.

Current status: We’re continuing our review of call stack logs related to the workload management module and suitability verifier in the directory layer, to identify the root cause before formulating a plan for remediation. We’re also analyzing connectivity issues and high latency in provisioning handler calls, and its impact on service performance.

Scope of impact: Any user who attempts to start Outlook (classic) when working in online mode or utilize 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 2:30 PM UTC