Outlook 2021 client getting disconnected from MS365 account while logged into Remote Desktop environment

We have a Microsoft Remote Desktop environment, currently 1 Gateway server, 3 RD Hosts in production and 1 RD host for testing. All servers are running Server 2019. We have FSLogix for “roaming” the user profiles. We have Microsoft Office 2021 LTSC installed on the RD Host servers.

Most of our users do NOT use Microsoft 365 accounts or the Outlook client in the Remote Desktop. We have a couple users that DO use the Outlook client, configured to their Office 365 account. They also use the OneDrive client in the Remote Desktop.

The problem is with Outlook, and sometimes OneDrive. I am working with one user mostly, but I have seen it happen to the other users.

Several times a day, the Outlook client will show as ‘Disconnected’ and the mail won’t sync. Sometimes OneDrive won’t sync either. But often, it is only one application, not both.

For Outlook, the user has found that she can sometimes Select File-> Office Account, and Sign Out of her Microsoft 365 account. Then close Outlook , wait a couple minutes and open up Outlook again. She will be prompted for her MS365 credentials, and then work fine for 2-3 hours. Then the process will repeat. We have also seen OneDrive lose it’s credentials. We know her MS365 account is fine, because she can immediately log into the MS365 webpage successfully and access Outlook mail and OneDrive files .

The problems only seem to happen when logged into Remote Desktop, which is using the FSLogix.

Interestingly, there is one RD Host that accidentally has a local user profile for her, and she almost never has a problem when connected to that RD Host.

That makes me think the problem may be specific to FSLogix.

I have recreated her FSLogix user profile, and the problem occurs again within the same day.

We have the latest version of FSLogix installed (version 2.9.8884.27471) and that didn’t help. I do have the Office 365 Containers enabled as well as the User Profile Containers.

I appreciate any thoughts on how to further troubleshoot, and what logs to look at to help resolve the problem. Or if you have a viable solution, even better!