Free the 80 port .

nginx.conf

server{
    listen 80;
    server_name example.com;

    location / {
        proxy_pass http://0.0.0.0:8002;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}