Login page problem, redirect

It works fine, it does not let pass the credentials that are not configured. But at the time of redirecting it to the other, it does not work.

session_start();

if (!empty($_POST)) {
    $isim = $_POST['login'];
    $sifre = $_POST['password'];

    var_dump($isim, $sifre);

    if($isim == 'teste' && password_verify($sifre, '$2y$10$OvT4fn4/S7cF2O4Rgr1hK.lhz0lKPaaEuyO/Bxn23HA7lFQEsCLoy')) {
        $_SESSION['auth'] = 1;

        header('Location: main.php');
        exit;
    }
}

After that it should redirect me to the "main.php" page, but what appears is a blank screen.

Ifyouwanttoaccesstoobserve:

username:test

password:test

link

I put this code, now I see other errors suppressed.

  

error_reporting (E_ALL);   ini_set ('display_errors', 'On');