We are currently using osTicket (v1.12.2) - I'm going to see if an update to the newer version will help. We are not getting any errors, which is making it challenging to determine what is happening.
I'll close a ticket and the green "Ticket # status changed to Resolved" appears, although nothing happens to the ticket and it remains open for a few minutes. I went back into the system and now it appears the tickets are no longer in the "Open" area - it looks like there is a delay vs. being unable to close them at this point.
I apologize for the confusion.
I'm not familiar with the web server/PHP info, which I'll need our head developer for.