Phalcon\Mvc\Dispatcher\Exception: DATA3\Frontend\Controllers\AController handler class cannot be loaded

<?php
 
use Phalcon\Mvc\Application;
 
ini_set('display_errors' , 1);
error_reporting(E_ALL);
 
$debug = new Phalcon\Debug;
$debug->listen();
 
/**
 * Include services
 */
require __DIR__ . '/../config/services.php';
 
/**
 * Handle the request
 */
$application = new Application();
 
/**
 * Assign the DI
 */
$application->setDI($di);
 
/**
 * Include modules
 */
require __DIR__ . '/../config/modules.php';
 
echo $application->handle()->getContent();