Error 503 Backend fetch failed

Hi, I have a script php feed products, this takes some time to perform everything.
Php.ini setting:
memory_limit = 2G
upload_max_filesize = 8G
post_max_size = 8G
max_execution_time = 60000
Web servers: Apache & Varnish Cache & Nginx Reverse Proxy
Apache version: Apache/2.4.29
PHP version: 7.1.9
MySQL version: 10.1.30-MariaDB

Unfortunately I get: Error 503 Backend fetch failed
Backend fetch failed

Guru Meditation:
XID: 163894

Varnish cache server

Error log: Script timed out before returning headers: datafeed_shopmania_prestashop.php

Hello Vincent.

I am in the same problem with yours.

Now I change server to APACHE ONLY, and it is solved. (I suggest you do this first, before get the solution)

I am still wondering why this is happened. Started form 16 jan 2018.

I also can not log in in client side. what about yours?

----
Asrofi
Indonesia

Even in apache only gives me the same problem !!!
What version of php do you use?

I can enter the client side, but I realized that CWP does not show the active domain both client side and admin side, also the domain does not take the php.ini data that are set, test done both admin and client side.

My PHP version: 5.6.30

Even in apache only gives me the same problem !!!
What version of php do you use?

I can enter the client side, but I realized that CWP does not show the active domain both client side and admin side, also the domain does not take the php.ini data that are set, test done both admin and client side.

I tried only apache with php 5.6.30 I always get the same error

Nobody can help me?
I had thought about buying the cwp pro but at this point I really believe that it does not suit me.