Firstly, the important bits:
OS: Ubuntu -Mate 20.04.2
NoMachine 7.4.1
I installed NoMachine on both client and server machines, and got it running perfectly over my home network. No problems at all.
Then, I ran the server machine in a headless configuration, i.e. no mouse, keyboard, monitor.
Problems:
When the desktop (which has been set for fullscreen (1920×1080)) opens, it is significantly smaller both horizontally and vertically. Around it the rest of the window is black.
Also, both the keyboard and mouse clicks are very slow to respond … a lag of at least one second.
I’ve tried to read the relevant docs, but I haven’t found any help. I’d very much appreciate help.