Posts to user list not going through ?

[John Dangler]

For the past 2 hours I've been trying to send messages and replies to
the group and am getting this back on every message - 

      To: "Ubuntu User List" <ubuntu-users at lists.ubuntu.com>
      Subject: Wireless - Dapper
      Sent:     Sat Dec 30 07:55:43 2006


did not reach the following recipient(s):
peter at gizmoman.net on Sat Dec 30 07:55:43 2006

      The e-mail account does not exist at the organization this message
 was sent to.  Check the e-mail address, or contact the recipient
 directly to find out the correct address.
      <beachbum-server.beach-bum-solutions.com #5.1.1>

This happens whether I am replying to a post, or starting a new post.

Is anyone else seeing this???