I'm running fedora core 8 mail and proxy server. When I create a user's email to be forwarded to his gmail account under the alias, the mail is returned with the ff errors.
The original message was received at Wed, 30 Nov 2011 15:15:03 +0200
from example.com [127.0.0.1]
----- The following addresses had permanent fatal errors -----
(reason: 550-Service unavailable; Sender address [email@example.com] blocked
(expanded from: <firstname.lastname@example.org>)
----- Transcript of session follows -----
... while talking to smtp.isdsl.net.:
>>> RCPT To:<email@example.com>
<<< 550-Service unavailable; Sender address [firstname.lastname@example.org] blocked using
<<< 550 sdom.bl.isdsl.net ; Access denied
550 5.1.1 email@example.com
... User unknown
How do I fix this? Please help!!