Fixing Google Play Billing Error "The item you requested is not available for purchase"

One of the most common issues when integrating Google Play Billing Library 7+ is the notorious error: "The item you requested is not available for purchase (BillingResponseCode.ITEM_UNAVAILABLE)".

The 7-Point Play Billing Verification Checklist

• Active Closed Testing Track: Your APK/AAB must be published to an active closed testing track and approved by Google review.
• License Testers Configured: Add tester Gmail addresses under Play Console > Setup > License testing with response set to RESPOND_NORMALLY.
• Matching Application ID and Keystore: The testing APK must be signed with the exact same keystore and have the same applicationId as the Play Console draft.
• Product ID Activated: Ensure your in-app product or subscription status is set to "Active" in Play Console > Monetize > Products.
• Merchant Account Verified: Ensure your Google Payments Merchant profile is active and verified.