REST Server Returns 403-Forbidden Error

Hi. I have installed a RESTful Server using https://github.com/chriskacerguis/codeig...restserver. I installed it using Composer and created a controller. When I test it using POSTMAN, I am getting 404 - Forbidden error message. What am I doing wrong.

Here is the controller.

PHP Code:

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

use Restserver\Libraries\REST_Controller;
require(APPPATH . 'libraries/REST_Controller.php');

class Webapi extends REST_Controller
{
    // Define global variables
    var $postData;

    /**    
    * @desc Class constructor
    * @author Allie Syadiqin
    * @access public
    * @param void
    * @return NULL
    */
    function __construct()
    {
        // Construct the parent class
        parent::__construct();

        // Load libraries
        $this->load->library('template/acd_api_lib');

        // Load models
        $this->load->model('template/acd_api_model');

        // Set XSS filtering
        $this->postData    = $this->input->post(null, true);

        // Define current time with local timezone
        $currentDateObj            = new DateTime("now", new DateTimeZone('Australia/Brisbane') );
        $this->currentDateTime    = $currentDateObj->format('Y-m-d H:i:s');
    }
    // End class constructor

    /**
     * @desc Endpoint to authenticate user
     * @author Allie Syadiqin
     * @access public
     * @param void
     * @return REST_Controller response
     */
    public function authenticate_post()
    {
        // Define variables
        $apiKey        = $this->postData['apiKey'];
        $providerId    = $this->postData['providerId'];

        printr($this->postData);
    }
    // End method authenticate_post()
}
// End class Webapi