The page for accessing most of the settings buttons is blank and returns to 404
JaMay
You need 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.
Cheers.
You are not running a supported web server (Apache/IIS). Since you are running nginx you might want to take a look at github to find what cfg changes you will need to make to get ajax requests to work. Or change to Apache.