Not sure if this is a Roku problem or an Amazon problem but I figured I'd start here. Trying to use the voice commands with Alexa and Roku, it plays Netflix with no problem, I can launch Prime Video but once I ask her to play anything she just tells me she had trouble communicating with Prime Video or Roku depending on the phrasing. Has anyone run into the same issue, or should I be posting on Amazon's forums?
I have looked over the support page you suggested and everything is in order, at this point I'm pretty sure it's a problem with the Alexa skill itself. I will head over to Amazon and post the question in their forum.