Wordpress get login errors from wp_signon in another function

Im using wordpress and I get a simple form to login users, which uses a login method from User class like this:

Login page

function login() {

  $result = User::getInstance()->login($this->email, $this->password);

  if ( is_wp_error( $result ) ) { 
    $this->hasErrors = true;
    $this->translatableError = 'La contraseña no es correcta.';
  } else if (isset($_COOKIE["lorraine-login-redirect"])) {
    $redirectUrl = $_COOKIE["lorraine-login-redirect"];
    setcookie('lorraine-login-redirect', '', time() - 3600, "/", $_SERVER['SERVER_NAME']);
    wp_redirect($redirectUrl);
    exit;
  } else {
    wp_redirect(site_url());
    exit;
  } 

}

User class

class UserStateAnonymous implements UserStateInterface {

  private $user;
  private $loginUrl;

  public function __construct($user) {
    $this->user = $user;
  }

  public function login($email, $password) {

  $creds = array(
    'user_login'    => $email,
    'user_password' => $password,
    'remember'      => false
  );

  return wp_signon( $creds, true );

}
...

So... I fill login form with bad credentials but Im getting null in $result variable whereas if I do var_dump(wp_signon( $creds, true )) inside login function in User class I'm getting an error about bad credentials.

Do you know whats going on?

Thanks