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

03/02/2026 9:11:00 AM

NHSmail Reference: INC46786979

Microsoft Reference: EX1268771

Issue Status: ONGOING

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.

Current Update: 03/02/2026 9:11:00 AM– Microsoft are finalizing our process to restart the Notification Broker service across the affected infrastructure, which they will anticipate may remediate the impact. In parallel, they are assessing options to implement long-term mitigation and telemetry to prevent further instances of impact while we continue our investigation into the underlying root cause.

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 update by: Friday, April 3, 2026, at 8:00 PM UTC