Calibre not working in Ubuntu 20.04 LTS

I tried to install calibre in Ubuntu 20.04 and it won't launch. I followed the instructions from another question (Calibre No Longer Working) but it didn't work. This is how I installed (version 5.20.0):

sudo -v && wget -nv -O- https://download.calibre-ebook.com/linux-installer.sh | sudo sh /dev/stdin

I'm getting this error:

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)

Any ideas?

Had the same problems on a fresh Ubuntu 20.04.3 LTS (focal) install. Solved it by doing the following:

1. Installed the latest Calibre version (5.32) using:

   wget -nv -O- https://download.calibre-ebook.com/linux-installer.py | sudo python -c "import sys; main=lambda:sys.stderr.write('Download failed\n'); exec(sys.stdin.read()); main()"
   

2. Installed the xcb library using:

   apt install libxcb-xinerama0
   

No problems any longer after that. Many thanks to all for the hints.

This post might solve your issue. Quoting from Calibre - Download for Linux page -

If you get an error Could not load the Qt platform plugin xcb you are missing some needed X11-XCB libraries, such as libxcb-xinerama0, for details see here