Microsoft 365 Alert – Service Degradation – Exchange Online – Some admins may have been unable to provision new mailboxes in Exchange Online – RESOLVED

Announcements Arpan Das

22/09/2025 16:21:00 AM

NHSmail Reference: INC46635533

Microsoft Reference: EX1157370

Issue Status: RESOLVED

Issue Description: Admins may have been unable to provision new mailboxes in Exchange Online.

More info: Some admins may have also been unable to assign licenses to new users.

Final Update: 22/09/2025 16:21:00 AM – Microsoft have manually restarted the remaining affected systems and confirmed that impact has now been fully resolved.

Scope of impact: Impact was specific to some users who were served through the affected infrastructure.

Root cause: A recent configuration update, deployed through our ECS, introduced an unexpected regression that led to impact.

Next steps: Microsoft are reviewing our ECS deployment procedures to better identify similar issues during their development and testing cycles.