Hi! As you probably have already seen, that credential not being validated is typically the result of the “View financial data” and “Manage orders and subscriptions” permissions not being granted. Can you let me know what happens when you attempt to make a test purchase?

I have 

None of the products registered in the RevenueCat dashboard could be fetched from the Play Store

when I call Purchases.getOfferings()

I also checked https://rev.cat/why-are-offerings-empty

Everything looks good.

On Google / 2, you say “Your app is published on a closed track and you've added a tester”

Do we really need to “submit” the app first? I did it, waiting for review. 

UPDATE:

After having submitted the app on closed track, Could not validate subscriptions API permissions was fine!

I was able to test in-app purchase only if I download the test app. It doesn’t work from VSCode or Android Studio. So not very easy to test, but at least it works.