The logs were not from the server unfortunately which is what we need in this case.
First, please try disabling hardware decoding on the computer you are connecting from when you encounter this issue. The instructions on how to do that are here: https://kb.nomachine.com/AR07U01202 but I will paste them here for convenience.
Exit the Player by going to the !M icon in the system tray and selecting “Quit NoMachine player”.
Edit the player.cfg file in the user’s home on the client side.
This file is:
$HOME/.nx/config/player.cfg on Linux and macOS and %USERPROFILE%\.nx\config\player.cfg on Windows.
Edit the “Enable hardware accelerated decoding” key and set the value to ‘disabled’.
For example:
<option key="Enable hardware accelerated decoding" value="disabled" />
Then open NoMachine again and connect to the problematic Linux host. Is there any change?
If that does not help, then we will require the full logs from the problematic server side with debug enabled. If I’ve understand you correctly, this is the Linux Mint 21.3 host. You can extract them using the automatic procedure here: https://kb.nomachine.com/DT07S00243. Send them to forum[at]nomachine[dot]com. Please use the title of this topic as the subject of your email. Thanks!