How to solve the problem - ERR_EMPTY_RESPONSE?

Question

Nginx

There are scripts in php, but the server is absolutely not loaded. The
usual current load is 0-1 people
, and now every other time there is an error ERR_EMPTY_RESPONSE and that's it, you have to press F5
sometimes you update the script, ERR_EMPTY_RESPONSE comes out and after a second the error SAMA disappears and the page gives the result of the execution script
how to solve?
new centos 7 server, software just installed with ispmngr 5 panel

Answer 1

See logs from backend