We have been using distribution lists for years and they work when you send to them from either an internal address or an external address. Yesterday I created a new list and it only works when you send to it from inside our network. I've made sure that the Message restrictions section on the properties is set to accept messages "from everyone". I've deleted it and created it over again, I've created totally different named lists and they all seem to not work now. But only the new ones, all the old ones are still functioning properly.