I have the following error message after sending an email to some domains.
What is the problem?
The original message was received at Wed, 31 Oct 2007 21:10:58 +0100
from localhost [127.0.0.1]
----- The following addresses had permanent fatal errors -----
<xxxxxx@gmx.at>
(reason: 550-5.7.1 {mx087} Sorry, your helo has been denied.)
----- Transcript of session follows -----
... while talking to mx0.gmx.de.:
>>> RCPT To:<xxxxxx@gmx.at>
<<< 550-5.7.1 {mx087} Sorry, your helo has been denied.
<<< 550 5.7.1 ( http://portal.gmx.net/serverrules )
550 5.1.1 <xxxxxxx@gmx.at>... User unknown