Echo Speaks and Fire Tablets

I have two Amazon Fire Tablets that I use as control panels. I'm having trouble getting Echo Speak to find either of these tablets. In Device Detection Preferences I have set the option to "create Devices for Tablets" and I also set the option to "override blocks and create ignored devices" ... but echo speak still doesn't locate either tablet. Am I missing something?

Did you ever have any luck with this? Echo speaks is only detecting my 11th gen fire tablet, not my 10th gen.