web server : internal server error

I have successfully installed vestaCP on centos 6.5 and already I add a swap file. I can access VestaCP well. But the web pages of user admin in the folder public_html can not be accessed with the message: Internal Server Error

I have tried to reinstall over 3 times but the result is the same

these are the errors ;

AccessLog ErrorLog Unduh AccessLog Unduh ErrorLog 70 baris terakhir dari ahli.website.error.log 2014/10/24 23:08:06 [error] 1321#0: *3 upstream timed out (110: Connection timed out) while connecting to upstream, client: 101.255.17.50, server: ahli.website, request: “GET / HTTP/1.1”, upstream: “https://x.x.x.x:8443/”, host: “ahli.website” 2014/10/24 23:13:00 [error] 1321#0: *7 upstream timed out (110: Connection timed out) while connecting to upstream, client: 101.255.17.50, server: ahli.website, request: “GET / HTTP/1.1”, upstream: “https://x.x.x.x:8443/”, host: “ahli.website” 2014/10/24 23:16:12 [error] 1321#0: *12 upstream timed out (110: Connection timed out) while connecting to upstream, client: 101.255.17.50, server: ahli.website, request: “GET / HTTP/1.1”, upstream: “http://x.x.x.x:8080/”, host: “ahli.website”

I try on Ubuntu 12.04 64, the problem is the same

What is the problem?