Microsoft has addressed an ongoing incident preventing customers from setting up multi-factor authentication (MFA) or accessing the My Sign-Ins platform.

"We're investigating an issue where some users may be unable to setup MFA or access the http://mysignins.microsoft.com website," the company's Microsoft 365 Status account shared on Twitter earlier today.

According to additional information shared in the admin center under MO1329260, those affected by this outage are seeing 504 Gateway Timeout errors.

"Some users may be unable to setup Multi-Factor Authentication (MFA) or access the mysignins.microsoft.com website. Users may encounter 504 Gateway Timeout errors when trying to access mysignins.microsoft.com," it said.

Since acknowledging the issue, Microsoft has switched to alternative healthy infrastructure to mitigate the impact and has added that it's now monitoring service telemetry to ensure full recovery.

"We've completed mitigation actions, including failing over to alternate infrastructure, and are continuing to monitor service health," Microsoft shared in the admin center.

"As elevated error rates persist, we're actively evaluating additional mitigation options, including optimizing how service requests are processed to further stabilize the service."

While the company has yet to share what regions are affected, it confirmed the issue around 5 AM ET and classified it as an ongoing incident, a flag commonly used to describe critical service issues with noticeable user impact.

Earlier this year, Microsoft also resolved a known issue that prevented some Microsoft Teams Free users from chatting and calling others, and an Outlook.com outage that prevented customers from accessing their mailboxes due to intermittent signing-in issues.

Update June 01, 08:41 EDT: Microsoft says it restored access to the My Sign-Ins service and blamed the incident on a recent cache configuration change.

"We've identified a recent cache configuration change required a failover," Microsoft said in an admin center update.

"During the failover, the service experienced high CPU and memory utilization as EU traffic peaked, which prevented the MySignIn service from processing the volume of requests. Mitigation actions have since been rolled back, and traffic has been restored to the original infrastructure."