Facebook login not working?

Question

Facebook

Hello everyone, I've run into a problem.
By clicking on the authorization button via facebook, it returns me to the main page where it should be, but does not want to work correctly.
When viewing the page through the source code and following the link from the source code everything works fine, what's the problem?
Handler code

if(isset($_GET['code']) && isset($_GET['state']))
{
  if($sessions = $facebook->getSessionFromRedirect()) {
    $_SESSION['facebook'] = $sessions->getToken();
    header('Location index.php');
  }

  if(isset($_SESSION['facebook'])) {
    $sessions = new Facebook\FacebookSession($_SESSION['facebook']);
    $request = new Facebook\FacebookRequest($sessions, 'GET', '/me', ['fields' => 'id, name, email']);
    $request = $request->execute();
    $fbuser = $request->getGraphObject()->asArray();
    setcookie("test", $fbuser['name'], 0, "/");
    print_r($fbuser);
  }
}