Socket connection is automatically closed on hero using nodejs

I am working on an IoT project. With nodejs on heroku I created a server on heroku. Then my IoT device will try to establish a connection. But when I tried it, the connection is closed automatically. Below I am using script. It works locally.

net = require('net');
var clients = [];
net.createServer(function (socket) {
  socket.name = socket.remoteAddress + ":" + socket.remotePort
  clients.push(socket);
  broadcast(socket.name + " joined the chat\n", socket);
  socket.on('data', function (data) {
    broadcast(socket.name + "> " + data, socket);
  });
  socket.on('end', function () {
    clients.splice(clients.indexOf(socket), 1);
    broadcast(socket.name + " left the chat.\n");
  });
  function broadcast(message, sender) {
   clients.forEach(function (client) {
      if (client === sender) return;
      client.write(message);
    });
    process.stdout.write(message)
  }
}).listen(process.env.PORT || 8899);
console.log("Chat server running at port 8899\n");

      

        
        
        
      

    

Please, help.