Users may experience errors or failures when accessing their mailbox via any Exchange Online connection methods

Microsoft issued an incident report on 13 Sep 2025 (Sat)

Users Affected	Any user using Microsoft Outlook Client Application for email service
Start Time	11 Sep 2025 (Thu) 9:50 PM
End Time	To be updated
User Impact	Some users may also experience delays in email delivery. The problem could impact some of Microsoft users attempting to access their mailbox using any Exchange Online connection method.
Incident Details	Current status: Microsoft (MS) has confirmed that service health remains stable across all connection methods, and the build deployment is progressing successfully across the remaining infrastructure. As build saturation continues, MS prepared to implement targeted actions if needed to maintain stability. MS will provide an earlier update if there are any significant changes in status or progress. Next update by: 15 Sep, 2025 (Mon) at 11:00 PM
Status	Microsoft is fixing the problem

Last update by Microsoft: 13 Sep 2025 (Sat) 9:59 AM

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