First, you may be able to use your old profile, as its settings for the account may still be current. Second, yes, you can install thunderbird and create a new account setting for your Spectrum account if you have the specfications for the account. Thunderbird's setup process knows settings for some email providers, but not all.

Thanks for the quick response. I have tried several of my old TB profiles, as well as try to create a new one. Nothing works. I have also talked to Spectrum support, but they give me the same settings that TB gives. I am including the TB Autodetect settings screenshot, and the Manual Configuration screen shot. Thanks for your help. Tom

One thing I forgot to mention. I am able to access Spectrum Webmail on the internet, but I cannot link TB to it. Thanks!

Try again, but omit the password. That works for some email accounts.

For a @new.rr.com account, I think you have to use these settings:

incoming IMAP: mail.twc.com, 993, SSL/TLS, normal password, email address

outgoing SMTP: mail.twc.com, 587, STARTTLS, normal password, email address

https://www.spectrum.net/support/internet/email-settings/