Gagal ambil session

if ($this->form_validation->run() == false) {

            $this->load->view('templates/header', $data);

            $this->load->view('templates/sidebar', $data);

            $this->load->view('templates/topbar', $data);

            $this->load->view('form/index', $data);

            $this->load->view('templates/footer');

            $this->load->view('form/index_vitamin');

        } else {

            $data = [

                'date' => $date,

                'time' => $time,

                'name' => $_SESSION['name'],

                'prener' => $_SESSION['id_prener'],

                'layanan' => $_SESSION['layanan'],

                'trackid' => htmlspecialchars($this->input->post('trackid', true)),

                'chanel' => htmlspecialchars($this->input->post('chanel', true)),

                'regional' => htmlspecialchars($this->input->post('regional', true)),

                'witel' => htmlspecialchars($this->input->post('witel', true)),

                'validation' => htmlspecialchars($this->input->post('validation', true)),

                'detail_invalid' => htmlspecialchars($this->input->post('invalid', true)),

                'ktp_validation' => htmlspecialchars($this->input->post('ktp_validation', true)),

                'detail_ktp' => htmlspecialchars($this->input->post('detail_ktp', true)),

                'dial_to' => htmlspecialchars($this->input->post('dialto', true)),

                'status_call' => htmlspecialchars($this->input->post('statuscall', true)),

                'reason_call' => htmlspecialchars($this->input->post('reasoncall', true)),

                'data_type' => htmlspecialchars($this->input->post('type_data', true)),

                print_r($_SESSION)

            ];

            $this->db->insert('form_data', $data);

            $this->session->set_flashdata('message', '<div class="alert alert-transparent text-center" role="alert">New Data has been added...

            </div>');

            //kembali ke halaman awal

            redirect('form');

        }

A PHP Error was encountered

Severity: Notice

Message: Undefined index: layanan

Filename: controllers/Form.php

Line Number: 104

Backtrace:

File: C:\xampp\htdocs\mandaa\application\controllers\Form.php

Line: 104

Function: _error_handler

File: C:\xampp\htdocs\mandaa\index.php

Line: 315

Function: require_once

kenapa gagal ambil session layanan yah