title: Facebook deauthorization callback is not called
body: <p>I have an FB app, when I enter as the deauthorization callback URL my development box address, the box is pinged with this request after app removal on FB:</p>
  
  <pre><code>POST /facebook/deauthorize HTTP/1.1
  Host: bashman.org
  Accept: */*
  Content-Length: 261
  Content-Type: application/x-www-form-urlencoded
  Connection: close
  
  fb_sig_uninstall=1&amp;fb_sig_locale=de_DE&amp;fb_sig_in_new_facebook=1&amp;fb_sig_time=1322732591.2685&amp;fb_sig_added=0&amp;fb_sig_user=1476224117&amp;fb_sig_country=de&amp;fb_sig_api_key=e39a74891fd234bb2575bab75e8f&amp;fb_sig_app_id=32352348363&amp;fb_sig=f6bbb27324aedf337e5f0059c4971
  </code></pre>
  
  <p>(The keys are fake here)</p>
  
  <p>BUT! when I enter my production box URL in the deauthorization callback URL, the POST request is never made. Tested it with Tcpdump. No request on my production machine, why?</p>
  
  <p>I checked with mtr the route from my production box to the IP address the request came from, all is OK, 0% packet lost.</p>
  
  <p>The hostname port and path is correct, tested it 1k times, no firewall, IDS, or other systems blocking my ethernet slot.</p>
  
  <ol>
  <li><p>Why is the Post callback not called? (How can I fix it?)</p></li>
  <li><p>How I can debug this to determine what the issue is?</p></li>
  </ol>