title: The check_path "/login_check" for login method "form_login" is not matched by the firewall pattern "^/admin/(.*)"
body: <p>I'm creating a website with <code>Symfony 2.8</code> and <code>FOSUserBundle</code> for authentication.</p>
  
  <p>I want the website to be public to anyone, and the back-office (with the prefix <code>/admin</code>) to be accessed after login authentication.</p>
  
  <p>I just keep getting the error:</p>
  
  <blockquote>
    <p>The check_path "/login_check" for login method "form_login" is not
    matched by the firewall pattern "^/admin/(.*)".</p>
  </blockquote>
  
  <p>My <code>app/config/security.yml</code> looks like:</p>
  
  <pre><code>providers:
  
      fos_userbundle:
          id: fos_user.user_provider.username
  
  firewalls:
  
      dev:
          pattern: ^/(_(profiler|wdt)|css|images|js)/
          security: false
  
      admin:
          pattern:            ^/admin/(.*)
          form_login:
              provider:       fos_userbundle
              login_path:     /login
              check_path:     /login_check
              always_use_default_target_path: false
              default_target_path: /admin
          logout:
              path:           /logout
              target:         /login
          anonymous:    true
  
      main:
          anonymous: ~
  
  access_control:
      - { path: ^/login$, role: IS_AUTHENTICATED_ANONYMOUSLY }
      #- { path: ^/login_check, role: IS_AUTHENTICATED_ANONYMOUSLY }
      - { path: ^/register, role: IS_AUTHENTICATED_ANONYMOUSLY }
      - { path: ^/resetting, role: IS_AUTHENTICATED_ANONYMOUSLY }
      - { path: ^/admin/, role: ROLE_ADMIN }
  </code></pre>
  
  <p>I know there's something wrong in the <code>form_login</code>, but I just can't really grasp it...</p>
  
  <p><strong>PS:</strong> <em>Similar questions have been asked, but without great answers (or answers that work for me, for that matter).</em></p>