how do i enable messaging

hi guyz i work as a system administrator for some organization(am a newbie). one of the solaris machines is loaded with the messenger server...all configured by a former administrator. my task was to create user accounts for the mail and calendar services and as i checked its not working .....i mean i couldnt send a message from one user to the other.....all the ports (pop,imap,smtp)seem to work fine and are open...what seems to be the problem and how do i fix it.????
:confused::confused: