This message usually indicates a problem on the receiving server. Check the
validity of recipients address as well as whether the receiving server is
configured to receive messages correctly. Resending the message will place
it again in the queue, if the receiving server is up and configured
correctly, message delivery should succeed unless the receiving server has a
policy to reject mail from your domain/ip (i.e. based on DnsBL) so make sure
it is not blacklisted. You can create a connector (SMTP connector to the
address space in question) that will relay through some other mail server
(you need to be able to relay through it), i.e. send all the mail to these
domains through another IP.
This posting is provided "AS IS" with no warranties, and confers no rights.
Please do not send email directly to this alias. This alias is for
newsgroup purposes only.