There is NO problem.*
Installing a distro version is madness. Flatpak more so.
Only install Viber and
Calibre from the main downloads, not Distro packages or Git.
* Options were explained
1) Installing the extra bits. It's a QT problem, not a Calibre issue. That works.
2) Mint 18.3 support expires April 2021, ANYWAY. Mint 19.3 (32bit and 64 bit) or Mint 20.1 (64 bit only) are the better solutions.
If there is the error on any particular Debian based Linux (inc Ubuntu and Mint), it will happen with other applications using QT.
Apply
Code:
sudo apt-get install libxcb-xinerama0
Doesn't take long. Problem solved.