Microsoft took down the Exchange Admin Center on October 12 after a code change left administrators facing an Internal Server Error when they tried to open it. The company first acknowledged the problem at 0937 UTC.
More than an hour later it said it had found unexpected 302 redirect errors and was analysing logs. The Register's headline says Microsoft blames a configuration change for the outage.
Source: theregister.com, reported 10-12. https://www.theregister.com/saas/2026/10/12/microsoft-blames-a-configuration-change-for-exchange-admin-center-tumble/5302698