User Profile

We are trying to adopt social sign in feature with 'sign in with apple'. We thoroughly went through documents and managed to successfully connect to apple sign in page from our website. However, when a user type in the information necessary to sign in, the id_token and the code in the response sent from Apple's server fail to reach our front end server and display 405 Method Not Allowed error. We believe this is the issue with the response_mode in the parameter of the link we use when the button('sign in with apple) is clicked. In our case, response_mode is set to form_post to get id_token and the users' email from scope parameter. It seems the form_post requests using POST method and this is getting blocked by AWS S3 or the CloudFront service that it nests in. We tried to change the way S3 and CloudFront work and let POST method get in but it seems it is not supported. What kind of measures can we take when we really need Apple users' email for sign up and sign in feature? It seems form_post mode is necessary if we want the userinfo we need.