Mail.app

[Miles]

Hi,
  I have a small question perhaps someone would know the answer to. One 
of the people here on campus has a G4 powerbook, 1GHZ 10.2.5 and cannot 
use the Mail.app to send mail from his machine. I am running an iBook, 
600MHZ, 10.2.5 and have no problem.
  We have tried making a new account and have had no luck with his 
machine no matter what we do. If I make the exact same settings on his 
machine then it still keeps asking for an account and password which 
never seems to work.
  He called Apple and they said that the server he is trying to access 
here on campus doesn't accept the type of authentication scheme that he 
is using. However, while I don't think I know more than Apple, I do 
know I can send messages absolutely fine with my iBook.
  I am wondering if someone else had come across some issue with the way 
that Mail.app was set up to authenticate. Perhaps he has changed some 
permissions, too. I had him run the DiskUtility and reset permissions, 
but that didn't work, either.
  I am pretty sure it is something fairly obvious and I just have worked 
with it enough that I can no longer see what the difference between our 
two machines is in order to institute the change to his is.
  Any ideas?
Thanks,
Miles