Unable to retrieve current server name

[hammedsadeghi]

Hi
I want to use WHMCS hooks in my cron in module that i wrote but i get this error on Hook request?
{"result":"error","message":"Unable to retrieve current server name. Please check PHP/vhost configuration and ensure SERVER_NAME is displaying appropriately via PHP Info."}
can you guide me?
i have writen a this hook for run my cronjob on whmcs cronjob task
add_hook('PostAutomationTask', 1, function($task, $completed) {
require_once(DIR.'/include/XXX.php');
XXX();
});