DanieleIT
Ah, you’d have to check your logs (general server logs, webserver error logs, PHP error logs, MySQL/MariaDB error logs, osTicket System Logs, Browser Console logs, etc.) for any related errors. However I will say that you are using an End Of Life version of osTicket so you won’t receive much assistance unless you upgrade to v1.17.5 or v1.18.1.
Cheers.