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Microsoft Exchange Online outage disrupting worldwide email and calendar access

Service Disruption
First reported
Last updated
Happening score
H score 25
1 unique sources, 1 articles

Summary

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Microsoft Exchange Online mitigated an outage that had blocked customers worldwide from accessing emails and calendars. The disruption also caused email delivery delays and mailbox connection failures, with some users seeing problems in Teams, Outlook, and Hotmail. Microsoft initially tied the problem to a portion of infrastructure in North America, then later said the issue was not region-specific. The outage mattered because it interrupted core communications and required recovery work, including a configuration change, before service returned to normal.

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Microsoft Exchange Online mailbox access disruption

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About this happening: The **Exchange Online** service is undergoing an **ongoing mailbox access disruption** that can stop some users from opening cloud mailboxes through **Outlook mobile** and the **n...

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Timeline

  1. 11.09.2025 22:43 2 articles · 8mo ago

    Microsoft Exchange Online outage disrupting worldwide email and calendar access

    Initial Disclosure

    Early on **September 11, 2025**, users began reporting **mailbox access failures** and connection problems across **Exchange Online**. Microsoft initially linked the disruption to a portion of **North America** infrastructure before later expanding the incident scope and working on mitigation.

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