422 Error when do post request of NGINX proxy

Question

I have set up an simple reverse proxy for http://github.com with config

server {
   listen 80;

   location / {
        proxy_pass https://github.com;
   }
}

When I go to localhost it display the github ui but when I try to login to github with the UI I got the Error 422 Unprocessable Entity

How can I fix this ?