I am having similar issue from all browsers.
I use following link to login, credentials are valid though. As soon as i clik on login, it redirects to the next page and repeats to provide password and the link displays as "https://www.spectrum.net/login/?ReferringPartner=TWC&loggedOut=true" Not sure. why loggedout coming while trying to login.
Login URL: https://www.spectrum.net