Hi Kevin,
there are 2 kinds of mail server in the world. Those that require authentication to send a mail, and those that don't.
For the ones that do you must set .authuser and .authpassword properties.
For the ones that don't you must _not_ set these properties.
Unfortunately there's no way to really "know" which one you are talking to, so most systems get the user to specify - as in "my mail server requires me to log in to send mail".
Cheers
Bruce