Jengas

<?php
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
ini_set('max_execution_time', 300); //300 seconds = 5 minutes. In case if your CURL is slow and is loading too much (Can be IPv6 problem)

error_reporting(E_ALL);

define('OAUTH2_CLIENT_ID', '1234567890');
define('OAUTH2_CLIENT_SECRET', 'verysecretclientcode');