It seems like Microsoft changed the default behaviour of how Windows 11 clients interacting with print servers. You can read more about it here.
On Windows 10 everything still works fine. On Windows 11 however, I get an error for insufficient permission. After changing the registry key Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Printers\RPC\RpcUseNamedPipeProtocol to 1, everything works as before again.
I have a kind of BYOD enviroment, so GPOs are not feasible. How can I fix this on UCS so that I don’t have to change this on every machine?