WordPress WP API Extending – 404 on Endpoints

I’m trying to create a few custom JSON endpoints for my plugin. I installed the WP API plugin and here’s the entire contents of my plugin php.

<?php
/**
 * Plugin Name: Quiz WordPress Plugin
 * Plugin URI: http://www.domain.com
 * Description: This plugin handles quiz functionality.
 * Version: 1.0.0
 * Author: Ray Hwang
 * Author URI: http://www.domain.com
 * License: private
 */
function quiz_api_init() {
    global $quiz_api;
    $quiz_api = new QUIZ_API();
    add_filter( 'json_endpoints', array( $quiz_api, 'register_routes' ) );
}

add_action( 'wp_json_server_before_serve', 'quiz_api_init' );

class QUIZ_API {
    public function register_routes( $routes ) {
        $routes['/api'] = array(
            array( array( $this, 'get_quiz'), WP_JSON_Server::READABLE ),
            array( array( $this, 'new_quiz'), WP_JSON_Server::CREATABLE | WP_JSON_Server::ACCEPT_JSON ),
        );
        return $routes;
    }
    public function get_quiz($_headers, $data = ''){
        return array ('a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5);
    }
    public function new_quiz($_headers, $data = ''){
        return array ('a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5);
    }
}

There are no errors when I activate the plugin. When I request the endpoint. I get

Not Found

The requested URL /api was not found on this server.

Apache/2.4.7 (Ubuntu) Server at ec2-----.compute-1.amazonaws.com Port 80

Does it have something to do with URL rewrite or permalinks?

My permalink settings is set to default http://ec2--------.compute-1.amazonaws.com/?p=123