I integrated InAppBilling to my app succesfully (with this guide: http://www.techotopia.com/index.php/Integrating_Google_Play_In-app_Billing_into_an_Android_Application_%E2%80%93_A_Tutorial), BUT when the "Google Play Box" appears, it says:
Error, Authentication required. Please login to your Google account.
I tried to buy things in other apps and everything was fine. It's just my app. Yes, I did exatcly what the guide and other sources said, but still:
NOT WORKING
Is there a solution for this?