Resolved -
Microsoft Issue-ID: EX1113110 Users may be unable to access their mailbox using any Exchange Online connection method
Impact: Outlook mailboxen zijn ontoegankelijk voor sommige gebruikers. Zowel via Outlook als Outlook-Web. Users may be unable to access their mailbox using any Exchange Online connection method.
Microsoft status-updates: 2025-07-13 19:00 We’ve confirmed the targeted deployment successfully resolved impact for the subset of infrastructure and started deploying the solution broadly to the rest of the affected infrastructure. The deployment is 28 percent saturated, and we expect this to reach 95 percent saturation by maandag 14 juli 2025 om 11:00 CEST
2025-07-13 06:24 The process of preparing the fix for the broader deployment is progressing, though taking longer than initially anticipated. We expect the deployment will start before our next scheduled update. Once the broad fix deployment starts, we expect it will reach 95 percent saturation within 24 hours. We’ll provide a more precise estimated completion time once we begin the deployment.
2025-07-12 09:30 We’ve confirmed based on our service health telemetry and confirmation from customers, that the majority of users are experiencing relief. We’re finalizing our comprehensive fix to address the underlying cause of impact, which we anticipate taking a few hours to complete, after which we’ll start our internal validation phase prior to deployment.
2025-07-11 23:35 To mitigate impact to users as quickly as possible, we’re adding additional database capacity within the affected infrastructure. We’re seeing steady improvements to service availability within our telemetry as this process continues. While this work is underway, we’re preparing a code fix to address the underlying cause of impact and fully remediate the problem. We anticipate that the remaining impacted users will see improvements in service availability as we complete these recovery steps.
2025-07-11 17:38 We're seeing continued impact after applying some infrastructure optimizations. We’re analyzing the cache configuration and authentication behavior in the affected environment to determine the underlying issue and identify the quickest path to remediate the impact.
2025-07-11 06:00 Our analysis of the portion of infrastructure responsible for traffic flow shows that requests aren’t being processed in an orderly fashion. We're working to determine whether this behavior is the root cause or a symptom, so we can identify the best path forward to help alleviate impact.
Jul 11, 09:22 CEST