title: Symfony 3: Undefined class constant 'AUTHENTICATION_ERROR'
body: <p>I'm working in an authentification system using Gard in symfony 3,</p>
  <p>When I use</p>
  <pre><code>$request-&gt;getSession()-&gt;set(Security::AUTHENTICATION_ERROR, $exception); 
  </code></pre>
  <p>inside</p>
  <pre><code>public onAuthenticationFailure()
  </code></pre>
  <p>I receive this error <em><strong>Undefined class constant 'AUTHENTICATION_ERROR'</strong></em></p>
  <p>how can I solve this problem?</p>