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) validation efforts are taking longer than initially anticipated, and is continuing to verify the efficacy of our secondary fix within her testing environment for an extended period. Next update by: 25 Sep 2025 (Thu)
Status	Microsoft is fixing the problem

Last update by Microsoft: 16 Sep 2025 (Tue)

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