Codeigniter is_cli_request() stops cpanel cron job from working

On my website I use cron job on cpanel.

I have this code below in the construct area of controller but it stops the cpanel cron job from working.

if (!$this->input->is_cli_request()) {
    show_error('Direct access is not allowed');
}

Question Do I need the code above. if I use my cpanel cron job? I just want to make it more secure.

<?php

class Cron extends CI_Controller {

    public function __construct() {
        parent::__construct();
        if (!$this->input->is_cli_request()) {
            show_error('Direct access is not allowed');
        }

        $this->load->library('email');
        $this->load->model('members_model');
    }

    public function message()
    {
        $admin_email = $this->config->item('email_host');
        $admin_email_pass = $this->config->item('email_password');
        $companyname = 'Riwaka';

        $config = array(
            'protocol' => 'smtp',
            'smtp_host' => 'ssl://mail.yourdomain.co.nz',
            'smtp_port' => 465,
            'smtp_user' => $admin_email,
            'smtp_pass' => $admin_email_pass,
            'mailtype'  => 'html', 
            'charset'   => 'iso-8859-1'
        );

        $this->email->initialize($config);

        $members = $this->members_model->get_approved_members_for_cron_job();

        if ($members) {

            foreach ($members as $member) {

                if ($member['approved'] == '1' && $member['approved_email_sent'] == '0')
                {

                    $this->email->set_newline("rn");

                    $this->email->clear();

                    $this->email->from($admin_email, 'Admin');

                    $this->email->to($member['email']);

                    $this->email->subject($companyname .' Account Approved');

                    $this->email->message('test');

                    $update = array(
                        'approved_email_sent' => '1',
                    );

                    $this->members_model->update_approve_email_send($member['email'], $update);

                    $this->email->send();

                }
            }
        }
    }
}