Losing Session Codeigniter

Question

Good afternoon guys, I started an internship and they gave me an Commerce to stir, it has Codeigniter (I had never touched)and a library called ion auth(for login) but when I login it sets the Session correctly, when going to the user panel where I need Session to identify the user Session appears as NULL, someone can give me a light?

if ($password === TRUE)
{
    if ($user->active == 0)
    {
        $this->trigger_events('post_login_unsuccessful');
        $this->set_error('login_unsuccessful_not_active');

        return FALSE;
    }
  //  echo '<pre>';print_r($user);echo'</pre>';
    $this->set_session($user);
    $this->update_last_login($user->id);
    $this->clear_login_attempts($identity);

    if ($remember && $this->config->item('remember_users', 'ion_auth'))
    {
        $this->remember_user($user->id);
    }

    $this->trigger_events(array('post_login', 'post_login_successful'));
    $this->set_message('login_successful');

    return TRUE;
}

When you enter this code in the controller the $_SESSION['user_id'] as NULL.

$idUser = $_SESSION['user_id'];
$qtdPedidos  = count($this->produtoscliente_model->getQtdPedidosCliente($idUser));
$qtdProdutos = $this->produtoscliente_model->getQtdProdutosCliente($idUser);