nginx php-fpm - Connection timed out - internal server error - upstream: "fastcgi://127.0.0.1:9001

[lokali]

im trying php-fpm with nginx on vps 512mb and i tried to install whmcs

i often get this error when executing whmcs installer:
internal server error

and when i checked my error log showing:
2016/02/07 16:50:54 [error] 16966#0: *2 upstream timed out (110: Connection timed out) while reading response header from upstream, client: 120.189.82.175, server: xxxxx.com, request: "POST /whmcs/install/install.php?step=5 HTTP/1.1", upstream: "fastcgi://127.0.0.1:9001", host: "xxxxxx.com", referrer: "https://xxxxxx.com/whmcs/install/install.php?step=4"

sometimes i get no error but sometime get error again when executing php

[SS88]

You will have to increase the timeout from it's default while you install WHMCS.

Check this, it's not specific to VESTA but will give you an idea of where you need to change the values: https://www.scalescale.com/tips/nginx/5 ... ing-nginx/