Sorry, your helo has been denied

This is the mail system at host server01.

I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can delete your own text from the attached returned message.

The mail system


host mx1.gmx.net[213.165.64.102] said: 550-5.7.1 {mx%}
Sorry, your helo has been denied. 550 5.7.1 (
http://portal.gmx.net/serverrules ) (in reply to RCPT TO command)

the solution was to edit the postfix main.cf change myhostname