I've had to make some email and computer changes recently: 1. First, Spectrum was making noises about shutting down my old @nycap.rr.com email account and making me use a newer @charter.net account I'd never used, BUT, it's they were able to sync everything up on their end so that I can use either email account through the Spectrum.net webpage, the old @nycap.rr.com (which I have continued to use) but with a new password, or @charter.net with a password specific to that account. On my old machine, I was still able to access the @nycap.rr.com address through Tunderbird using my new password, so now I want to continue using Thunderbird, just on my new computer instead of my old one. 2. Shortly after resolving the email issue with Spectrum, I got a new computer running LinuxMint 22 instead of the old computer that ran LinuxMint 18. When I tried opening Thunderbird on the new machine, it initially said it found my old @nycap.rr.com address with my recently changed password in Mozilla, but then couldn't link up with it at Spectrum, using either mail.twc.com (which Spectrum tells me is the correct server for my @nycap.rr.com address) or mobile.charter.net. Thunderbird did accept the new @charter.net email with the server mobile.charter.net, but that is NOT the e-mail address I want to use, not least because I have thousands of emails saved in my local files under my old email address. 3. Talking with a Spectrum tech support rep today, I changed the passwords for both of my email accounts with them, but Thunderbird would only accept the @charter.net address and its new password, and couldn't recognize the old @nycap.rr.com and its new password. How can I set up Thunderbird to use my old @nycap.rr.com address on my new computer? Thunderbird won't even allow me to try to set up using the old address because now it seems to only recognize the @charter.net address I was able to log in with. And setting up a new account with my old @nycap.rr.com address doesn't sound right to me. Do I have to go into the old machine and try to log in with the @nycap.rr.com address there and then do something? I'm at a loss.