In-app purchase does not work in a game store that previously worked in the market

I have a problem with billing in the application. When I connect to Google Play, it shows a message that

Service billing is currently unavailable. You can continue to use this application, but you will not be able to make purchases.

But before, I was able to connect with the market and make purchases. But this time it was the Android market, not the google play store. Can anyone help me solve this problem?