problems with smtp

[Joe Dunsmore <duns0014 umn edu>]

When I try to send a message with balsa, I get an error saying
"relaying refused
0:(null)
message left in your outbox"

I have redhat 9 and gnome 2.2.0.  This happened first when I tried it 
with the balsa 2.0.6 which came with my os and when i upgraded (through 
rpm) to the latest version.  I have no problems recieving mail.  I'm 
supposed to use authenticated smtp, so I use port 587.

thanks for any help you can give.