Wordpress translation of the theme, there is a .po file with the Russian language, but it is not used?

Question

WordPress

Installed the Houzez theme.
In the settings, I chose the language Russian.
The ru_RU.po and ru_RU.mo files are in the languages ​​directory, but the Russian language does not appear on the site in any way, I tried to install Spanish, the same thing.

I used this theme earlier, and there were no problems with installing the Russian language.
Those. somehow the theme or wordpress doesn't use language files.

I don't understand how to fix this.
Please tell me.

I contacted the developers of the Houzez theme, they answered me some nonsense, like translate manually through Loco, why translate if the topic already has a translation in the files ru_RU.po and ru_RU.mo, I have not received a response yet.

Answer 1

Does the system have a locale ru_RU?
What outputs locale -a?