location / {
        client_max_body_size 512M;
        proxy_pass http://192.168.1.2:3000;
        proxy_set_header Connection $http_connection;
        proxy_set_header Upgrade $http_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;
        proxy_set_header X-Forwarded-Proto $scheme;
  }

    error_page 500 502 503 504 /custom_50x.html;
    location = /custom_50x.html {
        root /usr/share/nginx/html;
        internal;
    }