Setting up Google Apps Connection

I’ve tried to repeat the whole process and it still doesn’t work; still with the same error. Where else should I look?

I’ve got two auth0 accounts; one for development and the new one for production. It was fine setting up Google Apps in dev. It’s just the new account that poses problem. I event tried creating a new OAuth client using my dev account, and still get the same error when I try it my Auth0 production account.