In the Android > Sample app > Trivial Drive when running the app I get the following when doing an IAP:
Error - Authentication is required. You need to sign into your Google Account
I've switched to a separate account on my phone with the testing account (i.e. the testing email address I've specified in the Developer Console) and followed all the steps here:
but no joy.
Any further suggestions?
I've since blasted away all Google Accounts on my phone and now have just 1 account - i.e. the Testing account.
And I've tried everything here: https://android.stackexchange.com/questions/20369/getting-authentication-is-required-when-trying-to-access-the-play-store