Microsoft 365 Alert – Service Degradation – Exchange Online – Some users may be unable to send or receive email messages in Exchange Online using Outlook on the web or desktop client – RESOLVED

03/12/2024 08:39:00 AM

NHSmail Reference: INC47232663

Microsoft Reference: EX946693

Issue Status: RESOLVED

Issue Description: Some users may be unable to send or receive email messages in Exchange Online using Outlook on the web or desktop client

Final Update: 04/12/2024 08:12:00 AM – The fix has been deployed, and Microsoft have confirmed the databases have returned to a healthy state and are functioning within acceptable thresholds. After monitoring to ensure service health was stable, they’ve verified impact has been remediated.

Scope of impact: Some users who are served through the affected infrastructure may be unable to send or receive email messages in Exchange Online using Outlook on the web or desktop client.

Root cause: A table responsible for updating indexes on calls to the database was deleted, as intended, by an internal process. However, the corresponding metadata to reflect that deletion did not update correctly due to an unexpected service error that occurred on a subset of infrastructure, which resulted in the impact.

Next steps: Microsoft are continuing to monitor the affected databases for any signs of unhealthy service. They’re developing wider, preventative measures to ensure this issue doesn’t return.