Your IP address appears not to be an email server.


I have a client that just received this message back after sending to one of their clients. This is the first time I have ever seen this. I followed the link that is provided below and I don’t think that my setup is wrong, but I could be wrong. I have never had another client report this to me, and I haven’t ever seen a message like this. I googled and found a few things about being black-listed, but I checked my server IP and it wasn’t on any list.

This is from the returned mail.

host[] said: 550-Your
message was rejected by this user and was not delivered. 550-Reason: Your
IP address appears not to be an email server.
550-Protection provided by: MagicMail version 1.2.2
550-For more information, please visit
the URL:

All help greatly appreciated.



I haven’t run into that error before either… however, it’s possible receiving server is rejecting it after comparing the sending users IP to a set of blacklisted IP’s. Perhaps the sender is sending directly from their dynamic home IP, rather than relaying through a mail server?

Some blacklists reject email unless it’s relayed through an email server of some sort.


the email came from my server, which of course uses Virtualmin and should be setup correctly. I haven’t had a problem, other than setting up the smtp server, with the emails. Now, my IP address is dynamic, but it is leased to me on a permanent basis. Maybe that has something to do with it.

Reading further into the email, the sender did write, If you are having a problem accessing my e.mail, please call and advise me. So this may be a new thing on their end. I will ask the client to contact the recipient.



It’s possible that, regardless of what you’re paying for, that your IP has been listed as dynamic/residential by a blacklist somewhere.

I’m curious, for example, if your IP shows up on any of the lists here:

not on any of the lists. Must be a configuration thing on their clients end.

Thanks for the help!