Hello @erich,
Veyon Master does not require any administrator rights to run. When trying with a non-admin user, did you try a local or domain user? In case of domain users, did you properly prepend the domain, i.e. MYDOMAIN\user? Did you also disable the "Perform access control" option in the master configuration (https://docs.veyon.io/en/latest/admin/reference.html#behaviour)?