Xfinity Stream works on phone, but not my roku tv

How come Xfinity Stream works fine on my phone using the app downloaded from the play store, but when I download it to my Roku TV, I get a message that says, "Unfortunately, we cannot support high speed data customers without a video subscription. Check out xfin.tv/shop to subscribe today!"

If I can use the app on my phone, why can't I on my Roku TV???