Hello,
I’m trying to deploy, my mern stack app, but it seems that something goes wrong, it is my first website, so can anyone help?

My server runs on the following ports:

API: localhost://5000
Frontend: localhost://3000
My server.js file looks like this:

const __dirname = path.resolve()
app.use('/uploads', express.static(path.join(__dirname, '/uploads')))

if(process.env.NODE_ENV === 'production'){

  app.use(express.static(path.join(__dirname, '/frontend/build')))  

  app.get('*', (req, res) => {
      res.sendFile(path.resolve(__dirname, 'frontend', 'build', 'index.html'))
  })
} else {
   app.get('/', (req, res) => {
     res.send('App Is Running...')
   })
}


app.use(notFound)
app.use(errorHandler)

const PORT = process.env.PORT || 5000

app.use((req, res, next) => {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  next();
});

app.listen(5000, () => {
    console.log(`Server Is Running In ${process.env.NODE_ENV} Mode  On Port ${PORT}`.yellow.bold)
})

When I deploy it, it doesn’t deploy successfully.

I Bought a node.js server and following the instructions that gave me a digital ocean,

When starting the server.js file:

root@obstacle-sports-node:~/Obstacle-Sports# pm2 start backend/server.js
[PM2] Spawning PM2 daemon with pm2_home=/root/.pm2
[PM2] PM2 Successfully daemonized
[PM2] Starting /root/Obstacle-Sports/backend/server.js in fork_mode (1 instance)
[PM2] Done.
root@obstacle-sports-node:~/Obstacle-Sports# 

This is my NGINX configuration:

        root /var/www/html;

        # Add index.php to the list if you are using PHP
        index index.html index.htm index.nginx-debian.html;

        server_name hellonode;

        location ^~ /assets/ {
                gzip_static on;
                expires 12h;
                add_header Cache-Control public;
  }

        location / {
                proxy_http_version 1.1;
                proxy_cache_bypass $http_upgrade;

                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;
                proxy_set_header X-Forwarded-Proto $scheme;

                proxy_pass http://localhost:5000;
        }

but when I am visiting IP address, I get This error

502 Bad Gateway
nginx/1.17.10 (Ubuntu)

please help :)