Spannersatcx is right. The reason it doesn't work now is for relaying reasons i.e. using someone else's mail server for spamming. Because you're no longer using FreeServe to connect to the net, their outbound server thinks your a foreigner trying to relay off their server and stops you. If you look at the error codes, you will see a 550 error. You can still pull the inbound mail from pop.freeserve.net, so no need to change the email address.