Multiplayer Problem

I have an Amazon Kindle Fire generation 2 and when I play minecraft I sometimes want to use multiplayer. When I try to use multiplayer it doesn't work but when I go to someone else's world it works because they have a iPod or some other device. When I want someone to go to my world, my world wont show up on there screen. I think because I have a kindle fire.

I'll be happy if you could fix that