I think Sage called it right when s/he suggested it could be a firewall/anti-virus problem. I recently got a new system, installed AVG antivirus software which I prefer and then spent several days fighting with one of the Norton program that would not let Mozilla Thunderbird, my email system, connect to the Internet.

   I finally blew out the Norton stuff entirely, suffering various dire threats that a million virii would fly up my nose, or whatever, and everything is working fine now. This is not to knock Norton, the program came with my computer, but I chose not to use it, in preference to another program.

   Dave