This fix is for cre loaded, oscommerce, zencart store using Authorize.net and are
1. hosted on godaddy or godaddy affiliated hosting
2. Authorize.net was working before but stop working all of a sudden and start generating “The server cannot connect to Authorize.net. Please check your cURL and server settings” error message

look for authorizenet_direct.php and comment out these lines with // or # so that the lines look like so:

//curl_setopt ($ch, CURLOPT_PROXYTYPE, CURLPROXY_HTTP);
//curl_setopt ($ch, CURLOPT_PROXY,"http://proxy.shr.secureserver.net:3128");

This modification is no longer needed on godaddy servers.