simscan smtp 451 mail server temporarily rejected message (#4.3.0)

[solarflare]

I have just rebuilt my mail server on freebsd version 7.2.  Out of the box it was working.  However, after a reboot I could not receive maiil.  When I use the simscan queue I get a 451 mail server temporarily rejected message error for all mail.  However, checking  /var/log/mail/smtp/current the mail is received fine into the server - ( CHKUSER accepted rcpt: from ... etc).

If I switch the queue to qmail-queue in tcp.smtp all is fine and the mail is received.  But no clam or spamd of course.

So what is the next step to check? Any ideas.