It appears for some reason Road Runner is blocking all attempts for our mailing list to send messages to anyone subscribed with a Road Runner account. Someone mentioned it was due to Comcast buyout but I am not aware of any of those details.
Only thing I can offer as a solution is to subscribe using another account (Gmail, Yahoo, AOL, Mac, or such) as I can not change Road Runners/Comcast server configuration to conform to common internet standards. You can complain to Comcast but good luck as ISPs are pretty bad for customer service.