hi,
i did all the instructions that you provide here, in your website, to add login via google and facebook, i followed everything and still can´t add the login or register. They are there but when click in, it gives 400 error.
Please provide the screens of your account to the private area as well as your site admin access. If you run the child theme and third parties plugins, please confirm the permit to deactivate for a while of checking what may take 15 minutes.