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Microsoft Exchange Online IMAP4 Access Disruption Due to Authentication Misconfiguration

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1 unique sources, 1 articles

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Microsoft is addressing an ongoing Exchange Online outage affecting IMAP4 access to mailboxes. The issue, tracked under EX1215307, stems from a code conflict in a recent IMAP deployment related to authentication support. The misconfiguration causes intermittent access problems for some users. Microsoft has deployed a fix and expects the issue to be fully resolved by the next scheduled update. Other connection methods remain unaffected. The incident was first acknowledged on Wednesday at 23:35 UTC. While the exact number of users and regions impacted is not specified, the issue has been flagged as critical in the Microsoft 365 admin center.

Timeline

  1. 08.01.2026 14:45 1 articles · 23h ago

    Microsoft Exchange Online IMAP4 Access Disruption Due to Authentication Misconfiguration

    Microsoft is addressing an ongoing Exchange Online outage affecting IMAP4 access to mailboxes. The issue, tracked under EX1215307, stems from a code conflict in a recent IMAP deployment related to authentication support. The misconfiguration causes intermittent access problems for some users. Microsoft has deployed a fix and expects the issue to be fully resolved by the next scheduled update. Other connection methods remain unaffected. The incident was first acknowledged on Wednesday at 23:35 UTC. While the exact number of users and regions impacted is not specified, the issue has been flagged as critical in the Microsoft 365 admin center.

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