I've implemented the Amazon IAP API 2.0 in my app and it works great with the local App Tester on my device; however in Live Test and Live versions I'm unable to purchase anything due to a failure to connect to the Amazon App Store, as said by a textbox that appears in the app after a while : "Amazon Appstore connection failure".
The logs I see from adb seem to confirm that there is a connection failure between the Amazon App Store services and my app. Here's a short log summary, I can link the whole log file if needed :
CommandServiceClient: Attempting to bind to service on com.amazon.venezia
CommandServiceClient: CommandServiceException happened, retriesLeft=0
com.amazon.android.b.f: COMMAND_SERVICE_BIND_FAILURE: null: null
AbstractCommandTask: Exception occurred while processing task: com.amazon.android.b.f: COMMAND_SERVICE_BIND_FAILURE: null: null
This exception happens multiple times until the error text box mentionned in my previous mail appears. Nothing above or below the log lines I've showed seem to point to the cause of failure. Tested with a OnePlus 6, Android 9 Pie (API level 28), Amazon IAP 2.0.76, Gradle 3.3.4 (lower than 3.4.0 so no R8 interferences). All my IAP items have been "Live" for about two weeks now so it's not because of that.