Problems with the list

[Konrad Scorciapino]

Hi,

I am getting a lot of error messages when sending emails to the mailing list. 
Here are some exemples:

Warning: could not send message for past 4 hours

From: 
Mail Delivery Subsystem <MAILER-DAEMON at ensim.com>


To: 
<konrad at scorciapino.org>


Date: 
Yesterday 22:00:25


    **********************************************
    **      THIS IS A WARNING MESSAGE ONLY      **
    **  YOU DO NOT NEED TO RESEND YOUR MESSAGE  **
    **********************************************

The original message was received at Thu, 10 Apr 2003 17:46:27 -0300
from 200-161-254-212.dsl.telesp.net.br [200.161.254.212]

   ----- The following addresses had transient non-fatal errors -----
<freebsd-questions at freebsd.org>

   ----- Transcript of session follows -----
... while talking to mx1.freebsd.org.:
>>> RCPT To:<freebsd-questions at freebsd.org>
<<< 450 Client host rejected: cannot find your hostname, [216.12.211.199]
<freebsd-questions at freebsd.org>... Deferred: 450 Client host rejected: cannot 
find your hostname, [216.12.211.199]
Warning: message still undelivered after 4 hours
Will keep trying until message is 5 days old


Is this a problem with my mail service or with the list?

Thanks