Sending messages to your e-mail address will be disabled if your bounce score goes above 5.0 or if there are configuration errors with the mail servers you are trying to use. If it's your ISP bouncing the e-mail then get a better ISP.
You can check and see if your address has been suspended at http://lists.freebsd.org/mailman/listinfo/ by following the links to mailing lists.
At the list page in question, type in your e-mail address in the very last field on that page, and click 'Unsubscribe or edit options'. On the next page, enter your password (you should get a monthly reminder of what your it is) and click 'login'. You'll be able to verify and modify your subscription status from the page you get to.