email problem

[rkruger at gawab.com]

Hi, 

Thanks for the reply. I have a smarthost at "smtp.gawab.com" which I may 
use. It requires authentication. After reading some docs on the net, I 
tryed to setup sendmail to talk to the smtp server, but I got the 
following error in a reply from the mail system:

... while talking to smtp.gawab.com.:
>>> MAIL From:<rpk at localhost.localdomain> SIZE=674
<<< 552 sorry, your envelope sender domain must exist (#5.7.1)
554 5.0.0 Service unavailable

Which setting in sendmail do I have to change to make it work?
It is really annoying how I send mail at the time. I have to type the 
email on my computer and bluetooth it to my phone to send.
Thanks for any help in advance.

Take care,
Rynhardt