Nginx reverse proxy ssl config

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I obtain certs for app1.server2.com (hosted on server 2) on server 1. check.
also it's unnecessary to obtain certs for server 2. check.

this is what I was using (which didn't work) for nginx app.1server2.conf on server 2:

ssl_certificate /etc/letsencrypt/live/app1.server2.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/app1.server2.com/privkey.pem;

server {
listen 80;

server_name app1.server2.com;
root /var/www/app1.server2.com;
index index.php index.html index.htm;

listen 443 ssl;

include /etc/letsencrypt/options-ssl-nginx.conf;

location / {
try_files $uri $uri/ /index.php?$args;
 }
}

as the certs are not needed on server 2 how would you suggest the .conf to work with ssl?