This incident has been resolved.

The Microsoft 365 team indicates that services are showing decreasing error rates in telemetry. They will continue to monitor service health status.

More details here: https://twitter.com/MSFT365Status/status/1371581388508573698

The Microsoft 365 team identified an issue with a recent change to an authentication system. They are rolling back the update to mitigate impact. They will provide an ETA as soon as one becomes available.

More details here: https://twitter.com/MSFT365Status

The Microsoft 365 team is investigating an issue with multiple M365 services. More details here: https://twitter.com/MSFT365Status/status/1371546946263916545

You can follow the status on their Twitter account: https://twitter.com/MSFT365Status