NoMachine cannot change screen resolution on a headless linux vm

After system upgrade on the remote virtual machine, NoMachine client can no longer resize the window, it's stuck at 800 x 600 resolution. To fix the issue, you need to stop and disable the desktop manager as you do not need it on a headless machine. See the follows:

sudo systemctl stop lightdm
sudo systemctl disable lightdm
sudo systemctl restart nxserver