Edge Syncing Problem

We have a problem with some of our users. When they want to sync their browser settings. They get an error: Not Syncing, Sync isn't available for this account.

The Sync button under Profile Settings in greyed out. On a test-user everything is working fine (Message: Sync is on)

License: M365 Business Premium
Edge version: 113.0.17743.5

Already checked the next things;

Device is Azure Joined

EnterPrise State Roaming = On

Get-AipService = Enabled

Get-AipServiceOnboardingControlPolicy --> UseRmsUserLicense = True

Added Regkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System --> NoConnectUser (DWORD) = 0

Does someone have another idea which I cloud test?

Thanks

Dennis