title: Symfony 5.1.2 page not found with new project
body: <p>I created a new project using Symfony 5.1.2, then I tried to run the server using
  <code>symfony serve</code>. Once I tried to access <code>localhost:8000</code>, I had this warning in the terminal : <code>[Web Server/PHP ] Jun 22 13:47:55 |WARN | SERVER GET  (404) / ip=&quot;::1&quot;</code>.</p>
  <p>Moreover, the page I had was symfony's default page saying &quot;#Page not found&quot;.</p>
  <p>I checked the existing routes and I had <code>default                    ANY      ANY      ANY    /</code>.</p>
  <p>I also checked the <code>DefaultController</code>, but everything looks fine, since it is the auto generated controller...</p>
  <p>I don't know what else to check, how could I get this default page working ?</p>