I dont know why in app purchase fails

Development Programming & Scripting
1

I did everything as required:

  1. Copied n pasted config/androidengine.ini of unrealmatch3 to my project.
  2. Extrapermission: android billing as a correct format.
  3. On googleplay, i created 6 in app purchases which have id of a~f.
  4. If i press buy button, make an in app purchase blueprint will be implemented with the ID from a to f.
  5. I literally tried everything, read all documents again and again, but it fails with debug output “not allowed”

In case, i packaged unrealmatch project and uploaded to googleplay, and it works perfectly.
Suspected factors:

  1. This project contains save & load function.

I really would like to know whch cases cause in app purchase to fail as “not allowed”