AUTH_TOKEN_VERIFICATION_FAILURE generally happens when Appstore SDK is not able to verify the Authentication token sent from Amazon servers. This generally happens when Public key (PEM file) is not available in the App. Kindly follow the steps mentioned in https://developer.amazon.com/docs/in-app-purchasing/integrate-appstore-sdk.html#configure_key to configure the key. Thanks!
So, after lots of investigation I finally made it working!
Here what you need to know, to make Production mode working:
1) It only works in Life App Testing! So Production mode will work only for apk that was downloaded from the store during LAT.
2) Make sure, that your AppstoreAuthenticationKey.pem is up to date. I my case for some reason it has changed after I initially downloaded it.
3) Follow other documentation guides.
Doing the sandbox testing was fairly easy. However to do test real money purchases, the app HAS to come from the Amazon App Store. Turning off sandbox mode alone does not work with local testing. Include the .pem file in the /assets directory, deploy a Live Test App, download it to your device, and only then you will get prompts to buy your in app purchases with real money.
In debug sandbox testing (on a Fire TV Cube device), I was able to get things working, even though the seemingly benign "AUTH_TOKEN_VERIFICATION_FAILURE" error still shows in the logs, by doing the following...
Some of these steps may be unnecessary, but this sequence worked for me, with the latest 3+ version of the SDK via Maven Central and public key included in the app, from the Amazon developer console.
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