Hi all. I am getting very sporadic bounce backs from people sending emails to my customer: #< #5.4.4 smtp;554 5.4.4 SMTPSEND.DNS.NonExistentDomain; nonexistent domain> #SMTP#. It is not a consistant fault but one that is seriously causing a problem as its always seems to be an important email.
It is only when external users are trying to send to my customer. External emails are fine.