boeingmagr
if it was working before, that means something change in your PHP mail, take a look at the error logs of your web server, PHP logs, and osTicket logs
The version of "osTicket version: 1.6 ST" is very old, should upgrade to 1.10.4
osTicket does not support "Webserver: nginx 1.14.0" should be using Apache or IIS
Also, your "PHP version: 5.2.17" is older too, should upgrade to version 5.6