Sign In with Apple - invalid_client

Hello,


I made this tutorial to implement Sign In with Apple on my page: https://developer.okta.com/blog/2019/06/04/what-the-heck-is-sign-in-with-apple


But actually I got "invalid_client" from the apple server. You could test it here: https://hanashi.dev/apple/


What do I wrong?


kind regards

Peter