Microsoft 365 Alert – Service Degradation – Exchange Online – Users may have been intermittently unable to access their Exchange Online mailboxes in some connection methods – RESOLVED

03/02/2026 9:11:00 AM

NHSmail Reference: INC46786979

Microsoft Reference: EX1268771

Issue Status: RESOLVED

Issue Description: Users may be intermittently unable to access their Exchange Online mailboxes in some connection methods.

More info: This issue may intermittently impact some users who attempt to access the Exchange Online service through the Outlook mobile apps or the new Outlook for Mac desktop client.

Final Update: 17/04/2026 9:27:00 AM– Microsoft’s has  confirmed that the deployment of the code change has completed saturation, and after a period of monitoring service health telemetry, they have observed the errors associated with the impact have ceased and the issue is resolved.

Scope of impact: Impact may occur intermittently for some users accessing their Exchange Online mailboxes in the Outlook mobile apps or the new Outlook for Mac desktop client. This section may be updated as our investigation progresses.

Next Steps: Microsoft are entering an extended period of monitoring to ensure the program they have implemented to identify and restart the notification service when persistent errors are detected successfully prevents this issue from reoccurring.