iPhone 3GS and Kindle Fire won't connect (or join game)

I want to be able to play on my iPhone and connect to my brothers Kindle Fire. We are using the same Wi-Fi source and both have the most updated version of MC PE. Both servers are visible and I checked the settings on both devices. I have connected before with the Kindle and iPhone. Only once. It does not work now.

If the Kindle Fire starts a game, and it's visible, the iPhone won't even pick it up. But the Kindle can connect to iPhone.

Steps to Reproduce:
1. Get a Kindle Fire and iPhone (3GS)
2. Start a game on the Kindle and try to connect with the iPhone
3. The iPhone won't pick it up