Hip Store iOS only works on about half of my idevices?

I have two ipads, two ipods, and four iphones. Hip Store iOS will only work on one of the ipads, none of the ipads, and one of the iphones. All of them have appsync 6.0 installed except on the ipads. I don't understand why it's not working. Please shed some light on this situation. By the way it's the first gen ipad with appsync 5.0+. Ipad 2 with appsync 6.0+. Two iphone 4's with appsync 6.0+. Two iphone 5's with appsync 6.0+. An ipod 4 with appsync 6.0+. And an ipod 5 with appsync 6.0+. Sorry for the messy format.

Plug it in