HTTPS is not working in LAN with nginx reverse proxy [closed]

I have SSL certificated domain name. It is working on internet but in LAN nginx forwarding the request to backend app. But this is not working. What is the problem?

server {    listen 80;    server_name finalProject.xyz www.finalProject.xyz;    # HTTP → HTTPS    return 301 https://$host$request_uri;}server {    listen 443 ssl;    server_name finalProject.xyz www.finalProject.xyz;    ssl_certificate /etc/letsencrypt/live/finalProject.xyz/fullchain.pem;    ssl_certificate_key /etc/letsencrypt/live/finalProject.xyz/privkey.pem;    include /etc/letsencrypt/options-ssl-nginx.conf;    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;    location / {        proxy_pass https://localhost:8443;        proxy_set_header Host $host;        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 https;        proxy_ssl_verify off;    }}