jiggs
1.8 is archaic at this point; I assume you instead mean 1.18.x. You’ll need to provide a little more information. Remember, screenshots are helpful.
It sounds like Apache isn’t configured correctly or PHP isn’t installed or setup correctly or even maybe PHP-FPM is installed just not configured correctly. So far it sounds like a setup issue, not an osTicket issue but we can determine that once we get more information.
Cheers.