First of all, see http://osticket.com/wiki/Email_Settings(http://osticket.com/wiki/Email_Settings), then check your osTicket settings. For eMail to work you need to have corresponding and correct settings in "Settings", "Emails" and "Departments". Turn on logging, as suggested in http://osticket.com/wiki/Installation(http://osticket.com/wiki/Installation) and check your logs. HTH.