Flutter App In-App Purchase Fix

I'm developing a Flutter app with in-app purchases (IAP) for iOS.

I already have:

The products approved and visible in App Store Connect.

A Sandbox account set up on the iPhone.

The products are correctly created and associated with the app.

I'm using the in_app_purchase package (from Flutter).

I have correctly configured the bundleId and Xcode.

Current issue: When running the code, the call to queryProductDetails() doesn't return any products (productDetails.isEmpty).

I also get errors like storekit_no_response in some cases.

I need:

Remote configuration review in App Store Connect and Xcode if necessary.

Verify that everything is ready to receive the products in the sandbox environment.

Check the Flutter code for any adjustments to how products are ordered.

Additional:

I'm using two environments (production and sandbox).

I'm using real developer accounts.

I need someone with specific experience in:

In-App Purchases on iOS (sandbox and production)

Flutter + in_app_purchase plugin

Xcode and App Store Connect setup