Curl working on localhost but not working on server - php

Question

so here is my problem ... I have a php-curl function that sends a POST Request to an API with a file as a parameter.
My Code is working perfectly fine on the localhost and its not working on my server.
Server Details
- Dedicated VPS windows server 2012
- Installed PHP 5.5 and MySQL 5.5 and phpmyadmin
- Curl is enabled ... && tried a simple curl function and its working fine
My app
- My Code is working perfectly fine on localhost but its not working on the server (i tried multiple servers with multiple specs)
$localFile=$_FILES['file_c']['tmp_name'];
$curl = curl_init($url);
if ((version_compare(PHP_VERSION, '5.5') >= 0)) {
$data = array(
'version' => '2017-01-20',
'file' => new CURLFile($localFile),
'config'=> '{"conversion_target":"normalized_html"}'
);
curl_setopt($curl, CURLOPT_SAFE_UPLOAD, true);
}else{
$data = array(
'version' => '2017-01-20',
'file' => "#".$localFile,
'config'=> '{"conversion_target":"normalized_html"}'
);
curl_setopt($curl, CURLOPT_SAFE_UPLOAD, false);
}
curl_setopt($curl, CURLOPT_CUSTOMREQUEST, "POST");
curl_setopt($curl, CURLOPT_USERPWD, $username . ":" . $password);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $data); // Insert the data
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
// Send the request
if(!curl_exec($curl)){
die('Error: "' . curl_error($curl) . '" - Code: ' . curl_errno($curl));
}else{ //do something else}
so this piece of code works fine on localhost but on the server it shoots a 500 internal server error
no errors in server logs
I've traced every single line in that code it breaks at the curl execution line
Please help
Thanks!