nginx only and php-fpm only 502 error

I'm starting to get pissed off that I bought a pro. After all, the server works only with apache. I choose nginx + php-fpm server and I have error 502, nginx + varnish + apache the same. The only thing that works is apache and php-cgi.

Screenshots:
https://imgur.com/a/uMW8bd3

Is it really so hard to set it up to work? I'm really getting irritated by this.

did you increased open file limit for that user account ?