Error API Login Facebook with PHP

Good afternoon, I'm finishing the login screen with PHP using Facebook API, at first I was able to click on the button I created and it already asked me to release the access on Facebook, this way I already managed to bring: / p>

ID , Nome , Picture of the user that is logging in, however XAMPP is now giving me the following error:

  

Fatal error: Uncaught InvalidArgumentException: The default access token must be of type "string" or Facebook\AccessToken in H:\Xampp\htdocs\projeto\lib\Facebook\Facebook.php:263 Stack trace: #0 H:\Xampp\htdocs\projeto\face.php(42): Facebook\Facebook->setDefaultAccessToken(Object(__PHP_Incomplete_Class)) #1 {main} thrown in H:\Xampp\htdocs\projeto\lib\Facebook\Facebook.php on line 263

Can anyone help me?

<?php 
session_start();
require_once 'lib/Facebook/autoload.php';

$fb = new \Facebook\Facebook([
  'app_id' => '-----------------',
  'app_secret' => '-----------------------------',
  'default_graph_version' => 'v2.10',
  //'default_access_token' => '{access-token}', // optional
]);

$helper = $fb->getRedirectLoginHelper();
//var_dump ($helper);
$permissions = ['email']; // Optional permissions

try {

    if(isset($_SESSION['face_access_token'])){
        $accessToken = $_SESSION['face_access_token'];
    }else{
        $accessToken = $helper->getAccessToken();
    }

} catch(Facebook\Exceptions\FacebookResponseException $e) {
  // When Graph returns an error
  echo 'Graph returned an error: ' . $e->getMessage();
  exit;
} catch(Facebook\Exceptions\FacebookSDKException $e) {
  // When validation fails or other local issues
  echo 'Facebook SDK returned an error: ' . $e->getMessage();
  exit;
}

if (! isset($accessToken)) {
    $url_login = 'http://localhost/projeto/face.php';
    $loginUrl = $helper->getLoginUrl( $url_login, $permissions);
}else{
    $url_login = 'http://localhost/projeto/face.php';
    $loginUrl = $helper->getLoginUrl( $url_login, $permissions);
    // usuário já autenticado
    if(isset($_SESSION['face_access_token'])){
        $fb->setDefaultAccessToken($_SESSION['face_access_token']);
    }//usuário não autenticado
    else{
        $_SESSION['face_access_token'] = (string) $accessToken;
        $oAuth2Client = $fb->getOAuth2Client();
        $_SESSION['face_access_token'] = $oAuth2Client->getLongLivedAccessToken($_SESSION['face_access_token']);
        $fb->setDefaultAccessToken($_SESSION['face_access_token']);
    }
    try {
      // Returns a 'Facebook\FacebookResponse' object
      $response = $fb->get('/me?fields=name, picture, email');
      $user = $response->getGraphUser();
      //var_dump($user);

    } catch(Facebook\Exceptions\FacebookResponseException $e) {
      echo 'Graph returned an error: ' . $e->getMessage();
      exit;
    } catch(Facebook\Exceptions\FacebookSDKException $e) {
      echo 'Facebook SDK returned an error: ' . $e->getMessage();
      exit;
    }
}
?>
<a href="<?php echo $loginUrl; ?>">Facebook</a>