Thanks Alva for the first sentences. I tried the things you wrote to me.
I tried to disable .htaccess file but the problem was not solved. I also tried domain.com/wp-admin but it didn’t resolve it.
I also tried to change permission for that directory from 750 to 755 but again, the problem was not fixed.
If the URL is helpful for you (or somebody else), here it is: https://www.artofwrestling.cz
