One more thing: xLanguage is not working with the static page. This is quite common plugin and I think a lot of people will have this problem. \
When I change the language, I am redirected again to the post page not to the static page. I think that this have something to do with the url. The static page is accessed like this https://dostoino-est.org/blog/ without parameters, but when I change the language the url have additional parameter: https://dostoino-est.org/blog/?lang=bg. So there is no way to change the language staying on the static home page.
If I remember correct, you need to have registration in www.remarpro.com. When you log in into your account you will find this key. I thin there is exact explanation for this if you look in google.