Microsoft 365 Alert – Service Degradation – Exchange Online – Users may experience errors or failures when accessing their mailbox via one or more Exchange Online connection methods – RESOLVED

Announcements Arpan Das

09/06/2026 11:06:00 AM

NHSmail Reference: INC46846524

Microsoft Reference: EX1384966

Issue Status: RESOLVED

Issue Description: Users may experience errors or failures when accessing their mailbox via one or more Exchange Online connection methods.

Final Update: 10/06/2026 09:28:00 AM – Microsoft are reviewing service monitoring telemetry to isolate the source of the issue and establish a fix.

Scope of impact: Impact is specific to some users located in the United Kingdom attempting to access their mailbox on Exchange Online via Outlook on the web.

Next Steps: Microsoft are further analyzing the affected subset of mailbox database infrastructure to help us determine the source for the degraded service performance, and in their efforts to prevent similar problems in the future.