make sure you are fulfilling all condition which are given below
1.Have you enabled In-App Purchases for your App ID?
2.Have you checked Cleared for Sale for your product?
3.Have you submitted (and optionally rejected) your application binary?
4.Does your project’s .plist Bundle ID match your App ID?
5.Have you generated and installed a new provisioning profile for the new App ID?
6.Have you configured your project to code sign using this new provisioning profile?
7.Are you building for iPhone OS 3.0 or above?
8.Are you using the full product ID when when making an SKProductRequest?
9.Have you waited several hours since adding your product to iTunes Connect?
10.Are your bank details active on iTunes Connect? (via Mark)
11.Have you tried deleting the app from your device and reinstalling?
If you answered “No” to any one of these questions, there’s your problem.
Also check this link. Hope this will clear your maximum doubt why your are getting invalid product.