There is another thread for this problem. One person reported that he got everything working. He did not list which generation fire 10 HD tablet he was using. I’m wondering if that variable makes the difference. I messaged him but he is either unable or unwilling to provide that information.
https://community.tablotv.com/t/stuck-at-verify-zip-code-screen-on-amazon-fire-hd-10-tablet/39079