Relay HELO'd using suspicious hostname. What's wrong?

Question

Email

I'm doing a newsletter, everything is fine, but one parameter spoils the statistics a lot.
This Relay HELO'd using suspicious hostname (IP addr 2).
CentOS 6, mailwizz, domain ukrup.com
What is the error and how to fix it? :(

Answer 1

Send mailings from a normally configured server with a static IP and correctly registered MX, A and PTR records in DNS. Well, do not forget to get the explicit consent of the owner of this address before including the address in the mailing list, otherwise you can get into some blacklist.