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If you are sideloading to test/debug your app, we do not recommend. We highly recommend you to use Live App Testing which you can use it from your developer portal.
We assume you are trying to address the issue with your app after we have conducted test on your app. If you need further more assistance with your app, please submit "Contact Us" form via developer portal as your inquiry seems to contain account specific information.
How can I test my app on Fire TV? 1 Answer
Failure [INSTALL_FAILED_TEST_ONLY] 0 Answers