How to Access Free this Week via Xfinity Stream on Fire TVs?

We have Xfinity Internet, Xfinity Cable for a TV, and Xfinity Mobile for Android Phones. I can access the Free this Week network on my Cable TV, but NOT on my Fire TVs at home (hard wired to our Xfinity Internet) or Mobile Devices, via the Xfinity Stream App.  I have spent hours trying to solve this, and another 30 minutes navigating this forum to ask this question. This is VERY frustrating!