Spectrum email stopped working in classic Outlook

If it keeps asking for the password even after you type the right one, Windows may be holding the old one. Open Credential Manager > Windows Credentials, delete anything with spectrum or charter in it, restart Outlook and enter it fresh. That fixed it here without having to remove the account.

First thing, log into Spectrum webmail in a browser. If that fails too, it's the account (password expired or got reset), not Outlook. If webmail works fine, the easiest fix is usually removing the account from classic Outlook and adding it back manually as IMAP rather than letting Outlook auto-detect it, auto setup often guesses the wrong server. Spectrum's support page lists the current incoming and outgoing server names and ports, copy them from there exactly, and tick 'my outgoing server requires authentication'. Your old emails stay on the server, so re-adding the account doesn't lose anything.