This is a sample nginx proxy config for forwarding nonstandard SSL port to other ip/domain with a custom port, not 443 standard https port

server {
listen 3000 ssl;
server_name xxx.domain.com;
error_page 497 301 =307 https://$host:$server_port$request_uri;

ssl_certificate /etc/letsencrypt/live/xxx.domain.com/fullchain.pem; # managed by Certbot
ssl_certificate_key /etc/letsencrypt/live/xxx.domain.com/privkey.pem; # managed by Certbot
include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

location / {
proxy_pass http://yyy.domain.com:3000/ip:3000;
proxy_redirect off;
proxy_set_header Host $host:$server_port;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Forwarded-Ssl on;

}