Setup inapp purchase for server side validation

Question

We are developing server-side validation of purchases.

We are using Windows.Services.Store API. At the stage when the server requests player's purchases we get an empty array.

Searching for a possible problem led to two similar options: - https://stackoverflow.com/questions/51968616/requests-to-microsoft-store-apis-always-return-empty-lists-of-products-subscri - If the product configuration has not been done and published through Partner Center, the calls to Collections will succeed but there will not be any results in the response. (https://learn.microsoft.com/en-us/gaming/gdk/_content/gc/commerce/service-to-service/microsoft-store-apis/xstore-v9-query-for-products)

How to properly configure inapp purchase for server validation?