title: PayPal IPN: unable to get local issuer certificate
body: <p>I am using curl to verify the PayPal IPN but it throws error: <code>SSL certificate problem: unable to get local issuer certificate</code>. The same code is working on development server and when I moved to client server it is not working.</p>
  
  <p>DO I need to purchase ssl certification in order to make payment via PayPal express checkout or any change in my coding part or any setting need to make on server.Curl is already enabled on server. Any help will be appreciated.</p>
  
  <p>My code below, and its a reduced test page for this:</p>
  
  <pre><code>$req = HAVING PARAMETERS FROM PAYPAL;
  
  $ch = curl_init("https://www.sandbox.paypal.com/cgi-bin/webscr");
  curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
  curl_setopt($ch, CURLOPT_POST, 1);
  curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $req);
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
  curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
  curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
  curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));
  
  curl_exec($ch);
  if(curl_errno($ch))
  {
      echo 'Curl error: ' . curl_error($ch);
  }
  </code></pre>