Error 520 not found

Hello,
For a while, he has the following error 520
I mean, it is not due to poor internet quality, or damaged php screpts.

I want to ask how can I fix this problem someone if there are ideas I would be grateful to share…

I also want to add when an error occurs 520, and restart apaceh (/etc/init.d/apache2 restart)
the site is reloaded without a problem, but after about an hour, two have to reboot again apache , because it still gives me a mistake 520

I will be glad if someone can offer me some ideas how to fix this problem

10x
br.

Here’s a collection of all 5xx errors. Please follow the steps in this posts:

This is great, but how can I check that the server is sending too many queries or that something is wrong, could be an example with commands

OS: Debian server 9

php v 7.3

10x