Microsoft Resolves My Sign-Ins Outage That Blocked MFA Setup

Microsoft has resolved an outage that prevented some users from accessing the My Sign-Ins portal and setting up multi-factor authentication (MFA).

During the incident, affected users trying to open mysignins.microsoft.com were met with 504 Gateway Timeout errors. The issue also blocked some users from configuring MFA or managing account sign-in security settings.

Microsoft tracked the problem in the Microsoft 365 admin center under incident ID MO1329260.

Users could not access sign-in security settings

The outage mainly affected users attempting to manage authentication and account security settings through the My Sign-Ins portal.

According to Microsoft, affected users experienced 504 Gateway Timeout errors, failed MFA setup attempts, and problems accessing sign-in activity and authentication settings.

The company classified the issue as an active service incident while elevated error rates continued.

Microsoft says cache configuration change triggered the issue

Microsoft later confirmed that the outage was caused by a recent cache configuration change.

As the company attempted to fail over traffic to alternative healthy infrastructure, the service started experiencing high CPU and memory usage. Microsoft said the issue became worse as European traffic volumes increased during peak usage hours.

The additional load prevented the My Sign-Ins infrastructure from handling incoming requests correctly.

Microsoft rolled back mitigation actions

To restore service, Microsoft rolled back the mitigation actions and redirected traffic back to the original infrastructure.

The company initially attempted to stabilize the platform by failing over to healthy systems and monitoring telemetry data.

However, elevated error rates continued for some time, forcing Microsoft to evaluate additional mitigation steps. Microsoft now says access to the My Sign-Ins service has been restored.

Microsoft recently announced several other Microsoft 365 and Windows-related updates, including a new Efficiency Mode for Microsoft Teams, a redesign for Microsoft 365 Copilot, and the new Surface Laptop Ultra revealed during Computex 2026.

Via BleepingComputer