title: Facebook does not show authentication when running under canvas
body: <p>I have a web site already integrated with Facebook login, using server-side authentication.</p>
  
  <p>I have an issue to turn it into an application running under Facebook.</p>
  
  <p><strong>The problem is that Facebook does not show the authentication page at all</strong></p>
  
  <p>Therefore, I am not even getting to the server authentication process for real.</p>
  
  <p>Right now, the application is running on my local machine.</p>
  
  <p>My app is defined as Facebook Application: (adding blank before localhost for site security purpose only)</p>
  
  <ul>
  <li>Canvas URL:  http ://localhost:4300/fbopt/ </li>
  <li>Secure canvas URL: https ://localhost:4303/fbopt/"</li>
  </ul>
  
  <p>[same problem happens when running in a Sandbox, without Secure URL]</p>
  
  <p>I have a "fan page" with "Go to App" button there. 
  Pressing a button leads me to the URL:
  https://apps.facebook.com/[appid]/?fb_source=timeline</p>
  
  <p>The browser starts loading the page with the frames.
  The lower frames makes the POST request to the URL I provided.</p>
  
  <p>My application redirects the page to the following URL:</p>
  
  <p>https://www.facebook.com/dialog/oauth?client_id=[appid]&amp;redirect_uri=https://localhost:4303/fbopt/hook&amp;scope=email,user_location,user_birthday</p>
  
  <p>I would expect Facebook to show up the application authentication form, with the permissions required.</p>
  
  <p>Unfortunately, this does not happen. <em>An empty page is shown within the frame, HTML is empty!</em> </p>
  
  <p>I see (from the Chrome network debugger) that the URL is indeed accessed, but the response is with HTTP 200 status (not error), but no response data. Instead, getting</p>
  
  <p>X-Frame-Options: DENY</p>
  
  <p>response header - rendering denied within frame! Why?</p>
  
  <p>When loading the URL above "manually" outside the Facebook frames structure, I do get the authentication screen with the right permissions.</p>
  
  <p>I wonder what is missing to get it work with canvas. </p>
  
  <p>Any hint on what I should add, or how to debug such a problem - will be appreciated.</p>
  
  <p>Thanks ,
  Max</p>