luckybackup-pkexec (como root) falla en Linux Mint Cinnamon 20.3

Question

Probé la falla en la terminal de la carpeta fuente de su aplicación para ver los errores. La pregunta es, ¿qué se necesita para reinstalar Qt? porque la aplicación ha sido eliminada y reinstalada dos veces.

root@LMC203DT:/usr/bin# luckybackup-pkexec
qt.qpa.xcb: could not connect to display 
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.

Aborted (core dumped)
root@LMC203DT:/usr/bin#