The "correct" IMAP and SMTP settings that Spectrum publishes may work for the gentleman who posted them, but as I say, the only thing we have been able to get to work is
Turn off automatically manage connection settings
Host name: mobile.charter.net IMAP: 993 Check Use TLS/SSL Authentication: Password (And on one of the computers, the host name that works is mail.charter.net.
SMTP
Account name: Whatever
Username: your email and Password
Host name: smtp.charter.net (and on the computer that uses mail.charter.net this is the mobile.charter.net)
Turn off automatic
587 Use TLS
Authentication Password
And remember, when your email stops spinning and you get the message "can't get there from here" and you try to click on ok, and it spins and you get "sorry, try again, this isn't going to work"... don't click okay. close out, reboot. Do this many times into what you actually put into these settings sticks. When I did this, I had to do it about a dozen times because no matter what I changed, the setting would get changed back, the automatic would show up clicked, the SMTP would change to 465, etc. And IMAP would change to POP settings.
Oh...here's something we discovered yesterday. The workaround use to be you could at least forward the email to another account (like a gmail that works). Nope. They've "Turned that off for security purposes." I don't know why we keep these two charter email accounts. They are nothing but spam, ads and phishing anyway. I use them for subscriptions, websites I follow, and shopping. Human beings we know send email to the other accounts.