🚀 go-pugleaf

Dear all,

I have recently come across the following error message in my
/var/log/maillog file.  It only seems to affect mail redirection to the
mail servers of Demon Internet Limited (www.demon.net).

        May 22 22:04:59 ns sendmail[23529]: KAA19275: 
        to=<???@???????.org>, delay=3+11: 45:44, xdelay=00:00:00, 
        mailer=esmtp, relay=punt-1.mail.demon.net., 
        stat=Deferred: 451 Nameserver timeout during parsing

(BTW I have changed the email address to ???@???????.org to prevent my
client being spammed.)

It is a real problem as the mail is currently stuck on my server.  I
have tried to find some documentation on this error message but have
failed so I would welcome any pointer anyone can give me.

Thank you in anticipation.
-- 
Peter Jenner