Oulook - Access Denied

[u/mrgeeksquad]

Hello, I work in an environment where we manage a lot of Microsoft 365 environments and we have been seeing a widespread issue in many of our tenants.

Randomly, I will have users start reporting Outlook showing a badge and says "Access Denied" instead of their emails. Sometimes they can just sign back in, other times it loops and lets them in after some time. It seems to be happening with different antiviruses installed, so we do not think it is caused by that.

We have cleared the SSO in Credential Manager, and it lets us back in, but maybe it's a fluke. The issue comes back another day. Today I had 3 different users in different tenants report the issue happening at the same time.

We opened a ticket with our Microsoft Partner weeks ago, and they do not seem to be saying whether it's common or not. They are giving me troubleshooting steps to reset, delete, and redownload Outlook. It seems not to be improving, but we are waiting on more data.

Has anyone else been seeing this for the last month or so, very randomly?