Why a Google Play code is refused and how to choose the right card.
Google Play gift cards only work in the country they were sold for. The country of your Google Play account must match the card. This is the most common reason for the error that the code cannot be redeemed.
Open play.google.com/redeem, or in the Play Store tap your profile icon, then Payments & subscriptions → Redeem code.
Google lets you change your Play country only once a year. Choose the card that matches your current country instead.