Troubles with Thundbird and twc.com sign up new laptop Windows 11

I use Thunderbird when Postbox acquired another. I am using 2 computers - desktop, old (10+ years), still Windows 10, and 2 two emails; new laptop (traveling), Windows 11. I download Thunderbird and set up my accounts - gmail.com and twc.com. Troubles with gmail.com, but finally I set up. However, I can't set up twc.com. I like twc.com-- no reason. (Time Warner Cable (twc) bought Spectrum. ) I can login twc.com webmail. Not Thunderbird. I looked carefully set up, Thunderbird searched, found "Host: mobile.charter.net" (Huh?, , continue, enter my password - "Error: ---". I removed VPN Windows 11, no difference. (Curios, my laptop and Firefox, my bank rejected connection. My desktop and Firefox still connects! I dread the day must update.) I am look forward yours reply. (Maybe Spectrum is searching to dump twc.com.) Jeremy Fields P.S. I wrote with my desktop - windows 10 -, my new laptop (windows 11) is problems