Microsoft 365 Alert : Service degradation – Exchange Online – Some users may be intermittently unable to access the Exchange admin center – RESOLVED

23/05/2022 01:14:00 PM (BST)

Microsoft Reference : EX383634  

NHSmail Reference : INC29121039

Issue Status : RESTORED

Issue Description : Some users may be intermittently unable to access the Exchange admin center.

Scope of impact : Any user trying to access the EAC may have been affected.

Final Update : 25/05/2022 08:49:00 AM – After monitoring the service over the last 24 hours, Microsoft have confirmed that the CPU utilization has remained at a healthy level post fix deployment. At this time, Microsoft are confident that access to the EAC has been fully restored.

Root cause : A background API request was returning an error under a specific scenario. Under normal circumstances our retry logic retries the request per standard process; however, because the API request continued to return the error it started an indefinite request loop. This behavior resulted in high CPU utilization on the components which facilitate EAC access, resulting in impact.

Next steps : Microsoft are reviewing how our service handles error requests to find ways to prevent the retry logic from triggering indefinite request loops in the future.