In order for jobs to run correctly on the farm, some form of authentication is necessary, typically using a network server such as a Active Directory for Windows servers or NIS/LDAP for Linux/OSX. It is recommended that your farm operate within some system so that all render farm machines can authenticate properly. If local user accounts are used, it is recommended to use the "proxy mode" for Qube Worker authentication.
If you have established a network-based authentication mechanism, it should be used for both desktop clients and render farm hosts. Therefore, all hosts in your farm should bind to the same authentication scheme so that authentication occurs consistently.