Nginx + nodejs, socket.io for https dosnt work - node.js

Question

I have a problem with customizing my nodejs app on the server (https, socket.io).
I using: pm2, nginx(works on port :3000), nodejs
Prev I customized nginx for :80 port(http) - works fine!.
But when I inserted ssl certificate and customized him I get errors in the console:
"Access to XMLHttpRequest at 'https://example:2053/socket.io/?EIO=3&transport=polling&t=NAPoEIt' from origin 'https://example.com' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
My nginx settings:
server {
listen 80 default_server;
server_name example.com www.example.com;
return 301 http://skinsgaben.com$request_uri;
}
server {
listen 443 ssl;
server_name site.com www.example.com;
ssl_certificate /var/www/site/ssl/example.crt;
ssl_certificate_key /var/www/site/ssl/example.key;
ssl_session_timeout 5m;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_prefer_server_ciphers on;
ssl_ciphers 'EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH';
location / {
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_set_header X-NginX-Proxy true;
proxy_pass http://localhost:3000/;
proxy_redirect off;
# Socket.IO Support
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
}
location /socket.io/ {
proxy_pass http://localhost:3000/;
proxy_redirect off;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}
error_log /var/www/site-log/error.log;
access_log /var/www/site-log/access.log;
}

Answer 1

I'm mostly using this pattern for local and remote nodejs apps.
let host = process.env.host || 'your host';
let PORT = process.env.port || 'your port';
let protocol = 'http';
let options = {};
if (APP_ENV === 'production') {
protocol = 'https';
options = {
key: fs.readFileSync(SSL.KEY),
cert: fs.readFileSync(SSL.CERT)
};
}
const server = require(protocol).createServer(options, app);
server.listen({ host, port: PORT }, () => {
console.log(`Server listening on `);
});