On Linux hosts with KDE Plasma desktop, video players like VLC and Kaffeine, and Vulkan-based video games, stop working after that NoMachine server v9.2 is installed- More in general all programs using OpenGL and websites using WebGL like Flight Radar 24 can be affected.

Since in case of a KDE Plasma desktop, the 'LD_PRELOAD=/usr/NX/lib/libnxegl.so' variable (used when the 'EGL' screen capture method is in use) is inherited by all applications, a misbehaviour in the NoMachine library libnxegl affects all OpenGL-based applications.  

As a temporary solution, disable EGL support in NoMachine by executing in a terminal:

sudo /etc/NX/nxserver --eglcapture no

Then re-login to the Linux host (logout and login to the system) or reboot the Linux machine.

Otherwise execute in a terminal:

sudo /etc/NX/nxserver --eglcapture no && sudo systemctl restart display-manager