Microsoft 365 Alert – Service Degradation – Exchange Online – Some users experience errors when attempting to create shared mailboxes in Exchange Online – ONGOING

Announcements Arpan Das

20/03/2026 16:49:00 AM

NHSmail Reference: INC46778719

Microsoft Reference: EX1256744

Issue Status: ONGOING

Issue Description: Users experience errors when attempting to create shared mailboxes in Exchange Online.

Current Update: 20/03/2026 16:50:00 PM – Microsoft are analyzing HTTP Archive format (HAR) logs to identify the underlying root cause and a mitigation plan.

Scope of impact: Your organization is affected by this event, and some users attempting to create shared mailboxes in Exchange Online may be impacted.

Next update by: Friday, March 20, 2025, at 5:30 PM UTC