Exim problem

[Mozzi]

Hallo all
After my recent problems I decided to give Exim a try.

I have only one problem.
I have managed to setup exim and get the mailhubbing done but if I send to
that host I get the following error on all messages
Both these adresses are known to work and were tested with other mx's

2003-03-19 10:33:02 H=(smtp.lantic.net) [196.25.53.195] sender verify fail for
<linux at mostert.nom.za>: Unrouteable address
2003-03-19 10:33:02 H=(smtp.lantic.net) [196.25.53.195]
F=<linux at mostert.nom.za> rejected RCPT <boer1 at boerewors.co.za>: Sender verify
failed

Tnx

Mozzi