The settings is only used for Zero or Single Sign-on to separate apps of network TV stations (ABC, NBC, CNN, etc.) that require your TV provider credentials AND support this feature.
Your Spectrum credentials are no longer valid for these apps, when you have no TV plan with them. You should change it to your current TV provider (regardless of ISP), if you use such apps separately, instead of the “combined” TV provider app. The TV provider app will work regardless, with its own sign in credentials.
TV providers that let you sign in on your iPhone, iPad, or Apple TV - Apple Support
Apps that let you sign in with your TV provider on your iPhone, iPad, or Apple TV - Apple Support
Sign in with your TV provider on your iPhone, iPad, or iPod touch - Apple Support
DirecTV app - App Store preview - Apple (US)