No resolver defined to resolve myipp.com in nginx on google cloud

Question

My puprose is to use nginx as a proxy for another application and I get an error above and I get 502 badgateway when I try to access my app.

My nginx configurations are shown below and I already unlinked the default nginx configurations but I still get the error below in /var/log/nginx/error.log.

Any clues ?

server{
  
listen 80 default_server ;
listen [::]:80 default_server;
server_name pivot.staging.ippen.space;

location / {
resolver 127.0.0.53
proxy_pass  https://$server_name:443/;


}

}

and when i used 127.0.0.1 / 8.8.8.8 as a resolver I get the folowing error:

nginx: [emerg] host not found in resolver "proxy_pass" in /etc/nginx/sites-enabled/custom_server.conf:9

I use nginx as a VM instance on Google cloud and I have two firewall rules (allow http and allow ssh access); OS is ubuntu 16.04.