I keep getting this error when I send mail to firstname.lastname@example.org.
'The following message to <email@example.com> was undeliverable.
The reason for the problem:
5.1.0 - Unknown address error 554-'mail from aa.aa.aa.aa refused, see http://www.spamcop.net''
aa.aa.aa.aa is the public ip address of my mail server. I am getting this error when I send mail to only this specific address. I have checked spamcop.net and my IP is not listed.