This is not an osTicket Awesome specific issue, but rather an osTicket one.
https://www.google.com/search?q=osticket+%22Unable+to+save+draft%22&rlz=1C1GCEA_enCA936CA936&oq=osticket+%22Unable+to+save+draft%22&aqs=chrome..69i57j0i22i30j69i64.4792j1j7&sourceid=chrome&ie=UTF-8