Hello,
Are you able to sign in to your Spectrum webmail using the same password? If the password does not work on the web, reset it through your Spectrum account since Charter manages IMAP authentication. If the password works on the web but Outlook still asks for it, remove the account in New Outlook and add it again using the correct IMAP settings from Spectrum. Microsoft supports IMAP setup, but your email provider controls the password and server access.