Dear @Elsaid ,
This happens because of the Wayland display server on Ubuntu. You can try specifying another display server.
If you launch SAMSON from a terminal, then you could first specify the environment variable QT_QPA_PLATFORM to use the Xorg display server (X11):
export QT_QPA_PLATFORM=xcb
Then start SAMSON in the same terminal. Note, SAMSON is installed in your home directory ~/OneAngstrom/SAMSON-Application/4.0.0/Binaries, you can try starting ./SAMSON-Launcher.sh
If this works, you can try disabling Wayland on your system, for that you will need sudo privileges:
Disable Wayland by uncommenting WaylandEnable=false in the /etc/gdm3/custom.conf
Add QT_QPA_PLATFORM=xcb in your ~/.bashrc file.
You might need to restart either the OS or the terminal.
You can check whether your system uses Wayland or X11 by running the following command in the terminal:
echo $XDG_SESSION_TYPE