Microsoft 365 Alert – Service Degradation – Microsoft 365 Copilot Chat – Some Microsoft Entra ID users see errors and are unable to use Microsoft 365 Copilot Chat in Outlook on the web – RESOLVED

Announcements Sharmista Mohanta

27/08/2026 10:12:00 AM

NHSmail Reference: INC46920493

Microsoft Reference: CW1462329

Issue Status: RESOLVED

Issue Description: Microsoft Entra ID users saw errors and were unable to use Copilot Chat in Outlook on the web.

More Info: While Microsoft focused on remediation, users with access to the Outlook desktop app could’ve used Copilot Chat through this client to bypass the impact.

Final Update: 27/08/2026 10:13:00 AM – Microsoft has confirmed that reverting the responsible change has successfully resolved impact by monitoring service health telemetry.

Scope of impact: Your organisation was affected by this event, and some Microsoft Entra ID users saw errors and were unable to use Copilot Chat in Outlook on the web.

Root cause: A recent service update contained an error, which resulted in this impact.

Next steps: Microsoft is reviewing the responsible update to better understand what led to the error that resulted in impact and prevent similar future occurrences.