I've been trying to send a message to an email address.
I keep getting something like this returned:
The original message was received at Mon, 29 Oct 2007 21:15:07 -0500 (CDT)
from (my email server) [my email server IP] (may be forged)
----- The following addresses had permanent fatal errors -----
<email sent to>
(reason: 550 5.7.1 <email sent to>... Relaying denied)
----- Transcript of session follows -----
... while talking to (recipient's email server).:
>>> RCPT To:<email sent to>
<<< 550 5.7.1 <email sent to>... Relaying denied
550 5.1.1 <email sent to>... User unknown
I am SURE that this email address is correct.