使用HTTPS发布请求对curl_exec（）进行空响应

Question

最近，我对我的URL进行了一些从HTTP到HTTPS的更改，一切都在使用HTTP，但是当我将其更改为HTTPS时，我在两侧curl_exec（$ soap_do）和curl_error上都得到空响应（ $ soap_do）。任何想法？

$url= "https://api.AppMain.svc?wsdl"; // asmx URL of WSDL

$soap_do = curl_init();
set_time_limit(0);
curl_setopt($soap_do, CURLOPT_URL,            $url); 
curl_setopt($soap_do, CURLOPT_AUTOREFERER,    true); 
curl_setopt($soap_do, CURLOPT_MAXREDIRS,      10);  
curl_setopt($soap_do, CURLOPT_FOLLOWLOCATION, true); 
curl_setopt($soap_do, CURLOPT_RETURNTRANSFER, true );
curl_setopt($soap_do, CURLOPT_SSL_VERIFYPEER, false); 
curl_setopt($soap_do, CURLOPT_SSL_VERIFYHOST, 2); 
curl_setopt($soap_do, CURLOPT_CAINFO, APPPATH . "/RSA/GeoTrustGlobalCA.crt");
curl_setopt($soap_do, CURLOPT_POST,           true ); 
curl_setopt($soap_do, CURLOPT_POSTFIELDS,  $xml_post_string); 
curl_setopt($soap_do, CURLOPT_VERBOSE,        TRUE); 
curl_setopt($soap_do, CURLOPT_HTTPHEADER,     $headers); 

// Converting
$response = curl_exec($soap_do); 
$error    = curl_error($soap_do);

if(curl_errno($soap_do))
{
    echo "Curl Failed: " . curl_errno($soap_do), "<br/>";
    echo curl_error($soap_do);

} else {

    echo "Success"; // I'm getting success result but when I print $response it's blank.
}