Codeigniter - session data won't set - php

Question

I have an issue setting session data. I want to set the session data to a boolean 'loggedIn' and an id 'userID'. For some reason when submitting the login form, the login() function will reach the line where it redirects to the dashboard() function, but then stops at the dashboard function.
Controllers
public function login() {
// echo 'login page';
$this->session->set_userdata('userID', NULL);
$this->session->set_userdata('loggedIn', NULL);
$data['session_data'] = array(
'userID' => $this->session->userdata('userID'),
'loggedIn' => $this->session->userdata('loggedIn')
);
$this->load->view('navigation');
$this->load->view('login', $data);
if ($this->session->userdata('loggedIn') == TRUE) {
$this->session->set_flashdata('error_msg', 'please log out to access this page ');
echo 'Please log out to access this page!...';
sleep(2);
redirect('index.php/user/dashboard');
}
if ($this->input->post('login')) {
$this->form_validation->set_rules('username', 'username', 'required');
$this->form_validation->set_rules('password', 'password', 'required');
$login_details = array(
'username' => $this->input->post('username'),
'password' => $this->input->post('password')
);
if ($this->form_validation->run() == true) {
$this->session->set_flashdata('sucess_msg', 'form running ');
$verify_password = $this->user_model->verify_password($login_details);
if ($verify_password == true) {
$this->session->set_flashdata('error_msg', 'password verified true ');
$userID = $this->user_model->get_userID($login_details);
$data_session = array(
'loggedIn' => TRUE,
'userID' => $userID
);
$session_loggedIn = array('loggedIn' => TRUE);
$session_userID = array('userID' => $userID);
$this->session->set_userdata('loggedIn', $session_loggedIn);
$this->session->set_userdata('userID', $session_userID);
//$this->session->set_userdata('loggedIn', $data_session['loggedIn']);
//$this->session->set_userdata('userID', $data_session['userID']);
$this->session->set_flashdata('success_msg', 'loggedIn and userID changed to current log in account ');
echo 'USER ID: ' . $this->session->userdata('userID');
//$this->load->view('dashboard', $);
redirect('index.php/user/dashboard');
} else {
$this->session->set_flashdata('error_msg', 'wrong email or password, try again!...');
//redirect('index.php/user/login');
}
}
}
}
public function dashboard() {
if ($this->session->userdata('loggedIn') == FALSE) {
$this->session->set_flashdata('error_msg', 'please log in to access the dashboard page');
sleep(2);
redirect('index.php/user/login');
} else {
$data['user'] = array(
'user' => $this->user_model->get_user_data($this->session->userdata('userID'))
);
$this->load->view('navigation');
$this->load->view('dashboard', $data);
}
}
Models
public function verify_password($login_details){
$this->db->select('password');
$this->db->from('user_account');
$this->db->where('username', $login_details['username']);
$query = $this->db->get->result_array();
if($query[0] == $login_details['password']){
return true;
} else {
return false;
}
}
Config
$config['sess_driver'] = 'files';
$config['sess_cookie_name'] = 'ci_session';
$config['sess_expiration'] = 7200;
$config['sess_save_path'] = APPPATH.'cache/sessions/';
$config['sess_match_ip'] = FALSE;
$config['sess_time_to_update'] = 300;
$config['sess_regenerate_destroy'] = TRUE;
Result
session data: Array ( [userID] => [loggedIn] => )
session data: Array ( [__ci_last_regenerate] => 1522538883 [userID] => [loggedIn] => )
The program will reach the first condition of the dashboard function and then redirect back to the login page because it says that the session data 'loggedIn' is not set to TRUE.