Fresh Tilix install reports "Configuration issue detected"

Ubuntu 18.04.4, tilix 1.7.7-1ubuntu2

I installed Tilix with "sudo apt install tilix".
On the first run, it reports "Configuration issue detected" and shows URL with instruction to fix it:

https://gnunn1.github.io/tilix-web/manual/vteconfig/

In the case of issue at Windows, I create screenshot and attach it to issues but such task is still not easy in Ubuntu (I miss easy to use program to work with bitmaps, something like MS Paint), so I am not going to attach any screenshot. Issue is easy to reproduce from my point of view...