Why is it, SuSE, that I can log on, log off but can't email to this list?

Using my standard email address I can sign onto the SuSE-linux-e list, and I can sign off of that list. I can download and read email from the list. BUT, I CANNOT send mail to the list. They bounce back with a message about needing a 'fully qualified name". If my jk05308@alltel.net is good enough to sign on and off, and download email from the list, why does it then pick my logon name and domain name (jerry@jerrykreps) as a gatekeeper? Makes no sense. JLK PS. I am sending this question via my Sony precisely because although my Beast can sign on to the list and download email from the list, any email replys or new email is rejected with the msg mentioned above.