Quote Originally Posted by cru22z View Post
Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET http://mmaapparel.com.au/ipn_main_handler.php?type=ec.

Reason: Error reading from remote server

Apache Server at mmaapparel.com.au Port 3128
Well, that's new news.
It shouldn't be using a proxy at all.
In fact the proxy settings were removed from view in 1.5.0 because they're largely obsolete.
The proxy capability was only added for a VERY OLD requirement that GoDaddy had many years ago, and even they have retired that about 3-4 years ago.

Your v1.3.9f should still have the menu options:
- Admin->Configuration->My Store->CURL Proxy Status .... should be set to FALSE
- Admin->Configuration->My Store->CURL Proxy Address ... leave it blank, instead of the address you've got there with port 3128.

Granted, the curltester script doesn't use the proxy, so it still sounds like your hosting company has added a proxy of their own, and changing any settings in Zen Cart won't change what the host has done to the servers/network/firewall.