When I click on the purchase, it says that such a product was not found, how to fix it?

Question

Android

Made in-app purchases. 4 goods, it turns out that one of the 4 goods only works. When you click on the rest, it says:
BuyProductID: FAIL. Not purchasing product, either is not found or is not available for purchase
What could be the problem and how can I fix it?

Answer 1

1) Inapp is not registered in the store
2) Inapp is not enabled in the store (for a specific country)
3) Payment testing is not configured
4) Another bunch of reasons to look for in the developer console on the store