Android In-App purchase doesn't work

I am about to publish the app to Google Play. I tested in-app purchases with the product ID android.test.purchase and it worked fine. Now I am trying to use the real product ID, but I always get the following UI error:

The item that you were attempting to purchase could not be found.

In the log I can see following:

D/Finsky(14007): [1] CarrierParamsAction.createCarrierBillingParameters: Carrier billing config is null. Device is not targeted for DCB 2. E/Finsky(14007): [3407] FileBasedKeyValueStore.delete: Attempt to delete 'paramstHSCrkH2npg__b-wWCeLSA' failed! E/Volley(14007): [3393] BasicNetwork.performRequest: Unexpected response code 500 for https://android.clients.google.com/fdfe/preparePurchase D/Finsky(14007): [1] PurchaseFragment.handleError: Error: PurchaseError{type=2 subtype=0}

I have done all the basic setup:

uploaded my apk to the alpha channel in developer console (to do that I had to shift my current date on PC 2 days back when releasing a signed apk), so the app status is "ready to publish" now
added real product id and set its status to "active", used same product id in my code
added license RSA key from console to my code
added tester gmail account to console license settings
installed on the device same released apk and use the tester gmail account there

What else am I missing?

Solution

The solution was to change the status "ready to publish" to "published" in the alpha channel. App will be not available in the market, but in-app purchases will work. Then if everything is fine, app can be moved from alpha to production.