Codeigniter会话不工作平板电脑

My code igniter application works fine in my PC , Laptop(browser IE11), and mobile also. But in my tablet sessions are not working. My session code are

$sess_array = array();
$sess_array = array(
     'id' => $row->id,
     'username' => $row->username,
     'role' => $row->role
   );
$this->session->set_userdata('logged_in', $sess_array);
$session_data = $this->session->userdata('logged_in');
$data['username'] = $session_data['username'];
$data['role'] = $session_data['role'];

Clear your browser cache and check. It will work. also check error_log file.

$config['sess_expiration'] = 6000;

Session Expiration is too big (84200), replace 84200 with 6000 or less, then check.