my sister is visiting and has Thunderbird email and uses bellsouth.net. She can't send or receive emails at my house. I use Road Runner from Time Warner. Are they incompatible?
PS I have been doing some research and have tried several different server settings - both pop and smtp settings and nothing seems to work
Your sister should be able to get things working by leaving the pop server as is, and updating the smtp server with the server for your location from this list:
I changed the smtp setting to server.triad.rr.com and still got an error message when I tried to send an email. She is however able to send and receive when she goes to ATT.NET - Email, News, Sports, Entertainment and Games