the forum could not working after I Installed Varnish

[HaMaDa4eVeR]

Hello,

I installed Varnish web acceleration on my dedicated server and everything is going great,
when I open forum the homepage it working well, but I cant open the forumdisplay page or any threat....
I got

HTTP Error 503 (Service Unavailable): The server is currently unable to handle the request. This code indicates this is a temporary condition, and the server will be up again after a delay.

error

the default port was changed from 80 to 82, I edited the file /include/class_core.php find on line 2003

// Get server port
		$port = intval($_SERVER['SERVER_PORT']);
		$port = in_array($port, array(80, 443)) ? '' : ':' . $port;

I insert 82 port

the forum work fine when I add 82 port to the domain (www.example.com:82/forum) otherwise did not work at all

the admincp work fine ....

what's the wrong or is there anything else I've to do ..!!

Regards,