Microsoft 365 Alert – Service Degradation – Exchange Online – Some users” Exchange Online email messages may be unexpectedly quarantined – RESOLVED

Announcements Arpan Das

24/03/2025 05:09:00 AM

NHSmail Reference: INC46483070

Microsoft Reference: EX1038119

Issue Status: RESOLVED

Issue Description: Users’ Exchange Online email messages may have been unexpectedly quarantined.

Final Update: 24/03/2025 08:57:00 AM – Microsoft’s have manually reallocated the remainder of the affected messages and confirmed that this issue is resolved.

Scope of impact: Impact was specific to some users who were served through the affected infrastructure.

Root cause: Specific URLs were miscategorized and quarantined by our anti-spam systems, causing impact.

Next Steps: Microsoft are continuing their investigation to determine the reason why the affected URLs were being miscategorized to better detect and prevent issues like this from occurring in the future.