Microsoft 365 Alert – Service Degradation – Exchange Online – Users may experience errors or failures when accessing their Exchange Online mailbox with any connection method – ONGOING

05/12/2025 08:26:00 AM

NHSmail Reference: INC46698761

Microsoft Reference: EX1192067

Issue Status: ONGOING

Issue Description: Users may experience errors or failures when accessing their Exchange Online mailbox with any connection method.

Current Update: 05/12/2025 08:22:00 AM – Microsoft are applying targeted fixes to reduce failures in the region and remediate the impact. This process is ongoing and requires multiple steps, so they are continuing to monitor service health telemetry as they apply these mitigations and actively adjusting their next steps accordingly.

Scope of impact: Impact is specific to some users located in Europe who are unable to access their mailbox with any Exchange Online connection method.

Root cause: A subset of Exchange Online service infrastructure that helps facilitate access to user mailboxes dropped below our manageable service performance thresholds, resulting in impact.

Next update by: Friday, December 5, 2025, at 7:00 PM UTC