Xfinity Stream and Roku

Just started using Stream on Roku. I have 3 TVs involved, each with it's own Roku, and everything is working fine on 2 of them, but on the 3rd one I can't get logged in and keep getting the error We're sorry/You don't have access to Xfinity TV. Obviously, I DO have access to Xfinity, as it is working on the other two TVs, and have been a Comcast customer for over 20 years!

I found some other threads similar to this, but they are of no help. 

Please help me!!