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Microsoft Exchange Online outage delaying external email with Server busy errors

Service Disruption
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Last updated
Happening score
H score 0
1 unique sources, 1 articles

Summary

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Microsoft is dealing with an ongoing Exchange Online outage that is delaying email to and from external domains, creating visible disruption for mail flow across multiple mailboxes. Users may see intermittent "Server busy" errors while sending or receiving messages. Microsoft says anti-spam protections may be worsening the impact, and it is still investigating the root cause and mitigation path. No recovery timeline has been provided yet.

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Microsoft Exchange Online service disruption causing authentication and email failures

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Latest development: 31.08.2026 20:30

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Open Happening

Timeline

  1. 04.09.2026 09:19 2 articles · 8h ago

    Microsoft acknowledges Exchange Online outage delaying external email

    Initial Disclosure

    Microsoft acknowledged an ongoing Exchange Online outage that is delaying email sent to and received from external domains, with users seeing intermittent "Server busy" errors across multiple mailboxes. The company said anti-spam protections may be contributing to the impact and that it is still investigating root cause and mitigation.

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