We do have a Trouble Report related to authentication with sudo which is not possible when requested for installing automatic updates from NoMachine repositories:
When running software updates, some GUIs run as root and on Wayland this is not allowed. This doesn’t seem to be your case though.
In your case, you appear to have two issues: 1) you can’t login to the server from remote, and 2) you can’t login locally as admin to server settings. Do you see the admin credentials dialog when you are trying to unlock the server settings locally.