Streaming on fire stick only showing default channels. On the home network.

I’d put this in your post:

Xfinity Stream on Fire TV is authenticating my Xfinity ID, but it is only showing the free streaming channels. I am an Xfinity TV subscriber and my paid TV lineup and premium channels are missing. This happens on a brand-new Fire TV Stick 4K. Please check my TV entitlements, Fire TV authorization, and in-home network recognition and escalate this to the Xfinity Stream team.