title: Android Volley BasicNetwork.performRequest: Unexpected response code 412
body: <p>I have this Error in my logcat.<br>
  I use Volley to send a request.</p>
  
  <pre><code>E/Volley﹕ [2040] BasicNetwork.performRequest: Unexpected response code 412 for http:/myserver/index.php
  </code></pre>
  
  <p>And nothing, no other error.<br>
  No line error, nothing.</p>
  
  <p>I don't know what to do.</p>