title: Invalid Credentials using Heroku URL as Canvas URL
body: <p>I am using Heroku to make a php application on Facebook. I want to have the Heroku URL be the Canvas URL in my application. However, when I put the URL in the Basic page and then try to open my application by going to <a href="http://apps.facebook.com/status_related_test" rel="nofollow">http://apps.facebook.com/status_related_test</a>, the canvas displays "Invalid credentials" and redirects to the URL of the application, <a href="https://young-warrior-3712.herokuapp.com" rel="nofollow">https://young-warrior-3712.herokuapp.com</a>.</p>
  
  <p>Any ideas what I might be doing wrong or how to fix this?</p>
  
  <p>ETA:<br>
  When I go directly to the application link (https://young-warrior-3712.herokuapp.com), I can sign in successfully. It is only when I try to go to the Facebook App page that it doesn't work.</p>