title: Facebook Real-time Updates: (#2200) callback verification failed, code 2200
body: <p>I am trying to get realtime updates from facebook for my application as documented in <a href="https://developers.facebook.com/docs/reference/api/realtime/" rel="nofollow">https://developers.facebook.com/docs/reference/api/realtime/</a>. I am struggling now when it comes back to the <em>Subscription Verification</em>. I have set up a callback server which accepts both GET and POST requests. I verified that the server works by making curl requests to it. </p>
  
  <p>However, I stil get this error when attempting to create a subscription issuing the POSt request below</p>
  
  <blockquote>
    <p>{"error":{"message":"(#2200) callback verification failed:
    ","type":"OAuthException","code":2200}</p>
  </blockquote>
  
  <p>From what I read in the documentation and other threads, I assume that this means that the single GET request to my callback URL fails. The callback url does not get requested by neither GET nor POST requests indeed. I suppose that facebook is somehow blocked from accessing the endpoint. However, I am able to auth as a user using the auth dialog (https://developers.facebook.com/docs/reference/dialogs/oauth/) where I pass a callback url on the same server as well. The server runs http (for now). </p>
  
  <p>This is the curl I am using to post the subscription. Host file has an entry to redirect dev.minggler.com to localhost =>( 127.0.0.1    dev.minggler.com)</p>
  
  <pre><code>curl -XPOST 'https://graph.facebook.com/256139341164822/subscriptions?callback_url=http%3A%2F%2Fdev.minggler.com%3A3000%2Ffacebook%2Frealtimeupdates&amp;object=user&amp;fields=friends&amp;verify_token=abcd123&amp;access_token=$MYTOKEN'
  </code></pre>
  
  <p>Can anybody help me out on this?</p>