title: Facebook page leadgen webhook returns error 102 Server Failure
body: <p>Facebook page leadgen webhook won't work for my page and associated app.</p>
  
  <p>If I test the webhook I setup with the <a href="https://developers.facebook.com/tools/lead-ads-testing" rel="noreferrer">testing tool</a> and click the "Track status" button, the issued realtime update object is associated to this error: <code>102 Server failure</code></p>
  
  <p>My facebook setup consist of:</p>
  
  <ul>
  <li>a business account</li>
  <li>an ad account</li>
  <li>a page</li>
  <li>an app that is subscribed to webhooks for the page leadgens. Testing the webhook from the app setup does effectively work (on <a href="https://developers.facebook.com/apps/:my-app-id/webhooks/" rel="noreferrer">https://developers.facebook.com/apps/:my-app-id/webhooks/</a>)</li>
  </ul>
  
  <p>Page, ad accoung and app all belong to the business, and the app seems to be correctly subscribed to the page : it is listed in the results of a graph api call to <code>/&lt;page-id&gt;/subscribed-apps</code>.</p>
  
  <p>Does anyone have an idea of what I could be missing ?</p>
  
  <p>Many thanks.</p>