使用cURL的PAYPAL问题

Question

I'm trying to create a payment (Paypal)

My data provided by paypal : https://developer.paypal.com/webapps/developer/docs/api/

$data = '{All the data}';

cURL..

$ch = curl_init();
 $headers = array(
      'Content-type: application/JSON',
      'Authorization: Bearer A101.YqvcjeJ6va_06Zd3ZQSkn8uNeH0Il1KJKCy72pc0ReSZ_n-cA9oEbVSArBc78F-e.iVCsmw63xoQHrfe7W1v_MYGHhUS',
            );

              curl_setopt($ch, CURLOPT_URL, "https://api.sandbox.paypal.com/v1/payments/payment");
              curl_setopt($ch, CURLOPT_VERBOSE, true);
              curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
              curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
              curl_setopt($ch, CURLOPT_POST, true);
              curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
              curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

              $response= curl_exec($ch);
              var_dump($response);
              $json = json_decode($result); 
              print_r($json);
              curl_close($ch);

The response:

[name] => UNKNOWN_ERROR
    [message] => An unknown error has occurred
    [information_link] => https://developer.paypal.com/webapps/developer/docs/api/#UNKNOWN_ERROR
    [debug_id] => 58039c1674622

So guys, what is wrong with my code? Thanks for the help!