I'm trying to implement in-app billing using Android, but I'm getting a weird error and I can't find anyone online with a similar problem.
I've done the following:
When I press the "Buy" button, it opens the store dialog, which says "This is a test order, you will not be charged". All seems good so far, but every payment method says "This payment method has been declined." so I'm unable to continue. This includes Google Play balance, Amex card, Visa and PayPal account.
I've tried the following, none of them worked:
Any thoughts on what might be wrong?
Google support have advised that the error is caused because the merchant account is "under review". They're looking into the reasons for the review and attempting to resolve the issue. I'll update this answer with their final response.
The best advice is to contact Google support through the merchant help centre: https://support.google.com/merchants
Update: Google fixed the account and it started working straight away. You definitely need to contact them to get this sorted.