title: "Incomplete response received from application" from nginx / passenger
body: <p>I tried to deploy my rails app on nginx and ubuntu via capistrano like the tutorial on the page <a href="https://gorails.com/deploy/ubuntu/14.04">https://gorails.com/deploy/ubuntu/14.04</a>. 
  but at the end i get an error message: </p>
  
  <pre><code>Incomplete response received from application
  </code></pre>
  
  <p>in my browser. 
  this is probably an error from passenger, but how can i figure out what to do?</p>