Same here. I can't cast the Spectrum TV app. The app is on a Roku but not on a Firestick. Its unbeleivable Spectrum does what it does. The money they spend on advertising should be spent on technolgy instead. I'm looking into Sling TV. By the way, I have been a TWC customer for over 15 years, so much for loyality.
Roku is the only supported set top streaming device outside of select Samsung smart tvs and the Xbox One. Roku paid for this exclusivity and until that deal expires there will be no support for Fire TV, Apple TV, Chromecast, or any other streaming device.
Although our Spectrum TV application does not support the Fire Stick there are
some of our partner applications that do. You can see those here:
Spectrum-Social Media Customer Care
Lead Moderator-Community Forums
Each channel App lists what devices they are supported on. AMC is online only.
It is my understanding ( I do not use The Fire Stick or Android devices myself) that
If it says Fire TV it would work with the Fire Stick. There are not many on the list
but there are some.