I tried that on 2 different devices and neither would connect. I also tried configuring my PC as a hotspot, and no Kindles would connect to that wifi network.
Ok, one device is connecting: Kindle Fire running Android app v0.9.86. Other Kindle fire running v0.9.87 will not connect, neither will Kindle fire running v0.9.88 or Pixel 3 running v0.9.88