[Exim] exim and mialman problem

i hope i have the right mialling list because i think this is a exim problem.

My problem is when a user like to join a mialling list then is that not a
problem if he mials from a host what i have in the database then is there
no problem.

But when a user like to join a mailling list whit a mail adres form is ISP
(and is not in my database) then i see the follow in mian.log

2003-10-28 01:00:32 unknown named host list "+relay_from_hosts"
2003-10-28 01:00:32 unknown named host list "+relay_from_hosts"
2003-10-28 01:00:33 unknown named host list "+relay_from_hosts"
2003-10-28 01:00:34 unknown named host list "+relay_from_hosts"
2003-10-28 01:00:34 unknown named host list "+relay_from_hosts"
2003-10-28 01:00:34 unknown named host list "+relay_from_hosts"
2003-10-28 01:00:35 unknown named host list "+relay_from_hosts"
2003-10-28 01:00:35 unknown named host list "+relay_from_hosts"
2003-10-28 01:00:36 unknown named host list "+relay_from_hosts"

i have no idea what the problem is. Can someone help me whit this ?

Greets Wouter