Microsoft 365 Alert – Service Degradation – Exchange Online – Users may be unable to access their mailbox using any connection methods – RESOLVED

Announcements Arpan Das

10/07/2025 08:39:00 AM

NHSmail Reference: INC46576249

Microsoft Reference: EX1112414

Issue Status: RESOLVED

Issue Description: Users may be unable to access their mailbox using any connection methods.

More info: More info: Impacted connection methods include, but may not be limited to:
– Representational State Transfer (REST) API
– Outlook on the web
– Exchange ActiveSync (EAS)
– Messaging API (MAPI)

Final Update: 11/07/2025 09:00:00 AM – The configuration change has fully saturated in all affected infrastructure. Microsoft have verified that the service is healthy by monitoring telemetry and confirming resolution with previously affected customers.

Scope of impact: Users attempting to access their Exchange Online mailbox using any connection methods may be impacted.

Next steps: Microsoft are analyzing performance data and trends on the affected infrastructure to help prevent this problem from happening again. They’re working to better understand the underlying cause of the event so that they can prevent similar issues from happening in the future, and to improve service resilience.