Microsoft restores Exchange admin centre after configuration error
A recent change caused administrators to receive internal server errors before Microsoft rolled it back.
Microsoft has restored access to the Exchange admin centre after a configuration change caused administrators to receive internal server errors. The company said reverting the change restored the service to normal, while a post-incident review is due to examine how the failure reached production.
The incident affected the Exchange admin centre, the web console used by organisations to manage Exchange Online. Microsoft acknowledged the problem at 09:37 UTC on Monday and said affected administrators could encounter an “Internal Server Error” when trying to access the service.
The company later said it had identified unexpected HTTP 302 redirects during access attempts. While the investigation continued, Microsoft told administrators that there was no workaround available, according to updates quoted by The Register.
Microsoft subsequently tested a rollback of the recent change. Its final update attributed the outage to a configuration change that produced unexpected responses in the affected request path and said reverting that change restored normal functionality.
The incident concerned access to an administration console rather than any reported interruption to ordinary email delivery. The Exchange admin centre is used for tasks including mailbox management, data migration and other administrative work, so the disruption could still delay operational changes for organisations that rely on the service.
Microsoft said it would review the change as well as its monitoring and telemetry. The company is expected to issue a preliminary post-incident report within two business days and a final report the following week.
The failure adds to a series of recent Microsoft 365 incidents in which configuration or deployment changes have been associated with service disruption. The Register has reported earlier problems affecting SharePoint and Outlook, although the causes and impact of those incidents were not the same.
Microsoft has not published an affected-tenant count or a detailed regional breakdown. The available updates also do not indicate that customer mailboxes were exposed or that the incident was caused by a cyberattack; they describe an access failure in the management service.
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The account is based on Microsoft’s quoted service updates and an independent technical report. The article separates confirmed service facts from information that remains unavailable, including the number of affected tenants.
- confirmed Administrators were unable to access the Exchange admin centre and could receive an internal server error. — The Register quotes Microsoft’s service incident description, and the status mirror records the outage. source
- confirmed Microsoft identified unexpected HTTP 302 redirects. — The Register reproduces Microsoft’s incident update. source
- confirmed The outage was resolved by reverting a recent configuration change. — The Register quotes Microsoft’s final update. source
- confirmed The Exchange admin centre is a web-based management console for Exchange Online. — Microsoft Learn describes the product in those terms. source
- confirmed Microsoft plans preliminary and final post-incident reports on different timelines. — The Register reports the timelines given in Microsoft’s update. source
- confirmed Microsoft has not published an affected-tenant count or detailed regional breakdown. — Neither the quoted incident updates nor the accessible status record provides those figures. source
- confirmed The available updates do not indicate a cyberattack or ordinary mail-delivery outage. — The published incident description concerns access to the EAC and attributes the issue to a configuration change. source
Editor's note
Microsoft’s incident updates and the independent technical report provide a clear account of the outage and rollback. Microsoft has not yet published the full post-incident report, affected-tenant figures or a regional impact breakdown.Sources
- Microsoft blames a configuration change for Exchange Admin Center tumble — The Register
- Exchange admin centre in Exchange Online — Microsoft Learn
- Status Page - Microsoft 365 — Microsoft 365 status mirror
More on this in other media
- The Guardian — „microsoft exchange online”
- BBC News — „microsoft exchange online”
- Sky News — „microsoft exchange online”