[Exim] ACL is NULL: implicit DENY

Hi all,

Problem: When I issue the rcpt to: SMTP command I get "550 Administrative prohibition" in the SMTP session, and "ACL is NULL: implicit DENY" in the exim debug.

I have just compiled exim 4.10 from source, and I am running it on my Slackware 8.1 host.
I am running exim as user=smtpd group=smtpd.
The command I run to get exim going is:
exim -bd -d all -q15m
I am using the default exim.conf file.

I have read all I can about the ACL's and I can not see anything wrong with them.

Any help would be great.

Thanks,
Daniel Cooper
Sydney, Australia