title: Credits callback script not called (error 1383046)
body: <p>I have a problem getting facebook to call my credits callback script. I've setup a company and the callback url. I used the example script for it. But nonetheless I always get this error when I try to access the payment window using the JS sdk.</p>
  
  <pre><code>var obj = {
      method: 'pay',
      order_info: order_info,
      purchase_type: 'item'
      // dev_purchase_params: {'oscif': true}
   };
  
   FB.ui(obj, getCashCB);
  </code></pre>
  
  <p>Error: </p>
  
  <blockquote>
    <p>There Was a Problem Processing Your Payment
    Sorry, but we're having trouble processing your payment. You have not been charged for this transaction. Please try again.</p>
  </blockquote>
  
  <p>error code from console: 1383046
  meaning:</p>
  
  <blockquote>
    <p>1383046   AppInvalidDecodedResponse   The application return value was invalid after json_decoding the return value.</p>
  </blockquote>
  
  <p>No matter if I'm in sandbox mode, set the callback url to something completely different.
  The callback script is never called.</p>
  
  <p>I've searched far and long for anybody else with this problem, but found nothing meaningful. There was something about the server accepting curl requests from facebook but I don't know what that means or how to test for it.</p>