Xfinity Stream on Roku

I just signed up for TV service.  I have a box but would like to return it and use my Roku exclusively to save on having to pay for the box.   Very often, when I start the app, it gets stuck on the "Initializing..." or it immediately goes back to the main menu screen of roku.  Restarting roku sometimes fixes it.  I've also tried resetting all of my network equipment.  Reinstalling the app seems to help