Microsoft blames configuration change for Exchange Admin Center outage

Exchange Admin Center goes down after configuration change

Microsoft took down the Exchange Admin Center (EAC) on October 12, 2026 after a configuration change left administrators facing an Internal Server Error when trying to access the service. The company first acknowledged the problem at 0937 UTC, noting that affected admins may encounter an Internal Server Error message when attempting to access the EAC. Any administrator attempting to access the console could be affected.

More than an hour passed before Microsoft provided additional detail, stating that it had identified unexpected 302 redirect errors during affected EAC access attempts and was analyzing diagnostic logs to isolate the source of the access failures. The company confirmed that administrators remained unable to access the EAC with no workaround currently available.

Rollback restores service

Two hours after the initial admission, Microsoft said it was continuing to test the rollback of the recent EAC change while monitoring the results to determine if this resolved the impact. The company confirmed in its final update that a recent EAC configuration change resulted in unexpected HTTP responses within the affected request path, preventing admins from successfully accessing the console. Reverting the identified change restored expected service functionality.

Microsoft assured customers it was reviewing the change to ensure it did not make the same mistake again, as well as its monitoring and telemetry, to improve detection and alerting for similar service behavior.

A familiar pattern of outages

This incident follows a pattern of similar outages attributed to configuration changes. In September 2026, a configuration change left some users unable to access SharePoint Online sites and pages. In April 2026, another change took down Outlook for iOS. In August 2025, Microsoft 365 experienced an outage because of yet another configuration change.

The latest outage was resolved before the end of the working day. A preliminary Post-Incident Report is due within two business days, with a final report due the following week.

Sources: Theregister