无法获得与heroku上托管的节点服务器的套接字连接

Question

我正在尝试将数据从一个节点服务器发送到另一个节点服务器。但是当我在heroku上托管一台服务器时，我无法获得套接字连接。 希望有人可以提供帮助。提前致谢

server.js

  var express = require('express');
        var socketIO = require('socket.io');
        var path = require('path');
        var value = "default";
        var PORT = process.env.PORT || 3000;


        // var engines = require('consolidate');

        // app.set('views', __dirname + '/views');
        // app.engine('html', engines.mustache);
        // app.set('view engine', 'html');

        var app = express();
        //var server =  app.listen(PORT, () => console.log(`Listening on ${ 
        PORT }`));
        var server = require('http').createServer(app);

        var io = socketIO(server);

        io.on('connection', (socket) => {
            console.log('+Client connected successfully+');
            socket.on('data', function (data) {
                console.log('data from pi' + data);

            });
            socket.on('disconnect', () => console.log('Client 
        disconnected'));
        });

        //console.log(PORT + 'actual listening to'+server.address().port);
        server.listen(PORT);

        client.js
        var io = require('socket.io-client');
        var socket = io.connect('https://herokuappname.herokuapp.com/', { 
        reconnect: true });

        console.log('2');

        // Add a connect listener
        socket.on('connect', function (socket) {
            console.log('Connected!');

        });