Microsoft 365 Alert – Service Degradation – Microsoft 365 suite – Users are unable to access Microsoft 365 Copilot Chat or portal.office.com – RESOLVED

Announcements Shagufta Naaz

12/06/2026 09:20:00 AM

NHSmail Reference: INC46850041

Microsoft Reference: MO1387691

Issue Status: RESOLVED

Issue Description: Users are unable to access Microsoft 365 Copilot Chat or portal.office.com

More info: Admins may have been able to access the Microsoft 365 admin center via admin.cloud.microsoft as a temporary solution. Additionally, Copilot in Microsoft Teams was not impacted and could have been leveraged in the interim while we mitigated the issue.

Final Update: 12/06/2026 09:20:00 AM – Microsoft has successfully rolled back the change throughout the affected infrastructure, and we’ve confirmed with previously affected users that the impact is mitigated.

Scope of impact: Any user or admin may have been affected by this event.

Root cause: Microsoft are identified an issue with a recent deployment which is contributing to impact. They will provide more information in our Post-Incident Report.

Next steps: Microsoft are analyzing the recent deployment to identify why this issue occurred and how to prevent it from happening again in the future.
– They are reviewing our change management processes to determine areas of improvement.