I figured this out. As a huge Tech N9ne fan, this was driving me crazy. Alexa would recognize my speech and play my Pandora Tech N9ne radio, but would default to that other artist when trying to play off of Amazon music. I know this is an old post, but I hope I can still help people. The fix is to sign in to Amazon Music on another device, create the Tech N9ne radio station, and voila! Alexa will now cooperate and play the REAL Tech N9ne!