Unity IAP not working on android build

I implemented a simple IAP manager in my game, so you can purchased the game currency for $.99, and it works on my unity project, a prefab called “UIFakeStoreCanvas” gets instantiated in the scene view.

But when i build it to android, and press the button to get the"UIFakeStoreCanvas" to instantiate, nothing happens!
Is anything going wrong here?

same problem is occurred.
If your problem is resolved, please help me.

IAP Catalogy is added, this problem is resolved.