digitalFAQ.com Forum - Remote host said: 451 4.3.5 Server configuration error

I was setting up a new server a few months ago, and messed up the DNS records.
This is what happened when a hostname was not specified.

Code:

Hi. This is the qmail-send program at yahoo.com.

I'm afraid I wasn't able to deliver your message to the following addresses.

This is a permanent error; I've given up. Sorry it didn't work out.



<test@domain.com>:

10.20.30.40 does not like recipient.

Remote host said: 451 4.3.5 Server configuration error

Giving up on 10.20.30.40.

I'm not going to try again; this message has been in the queue too long.

At least I think that's what caused it. (Should have posted this when the issue happened and was fixed, not months later. Oops.)