I try to make a validation of purchases on the server, but it can't to make a request to Google Play Android Developer API. After a request it shows this one:
Error calling GET https://www.googleapis.com/androidpublisher/v1.1/applications/my.app.id/inapp/my_in_app_purchase/purchases/purchase_token: (403) Forbidden
If I make a validation of this purchase by the test form in Developers Console, everything is OK and Google API would send a response.
Requests to other API (for example Books API) works fine.
To work with API I use Google APIs Client Library for PHP. Authorization goes by Service Account. In Developers Console access to Google Play Android Developer API is on.