cors settings in https - ssl

Question

My node applications runs fine with http but in https it throws cors error and my ssl port link (https://www.example.com:3001) works fine and loads.. So ssl settings are fine but the cors issue is not allowing to submit the form..
The following is the code for http which is working fine.. Can anyone check and fix the issue..
var express = require('express');
var DataController = require('./user/DataController');
var UserController = require('./user/UserController');
var db = require('./database/dbbase-db');
var cors = require('cors');
var app = express();
app.use(cors());
app.use(function(req, res, next) {
res.setHeader("Access-Control-Allow-Origin", "https://www.example.com");
res.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
res.setHeader('Access-Control-Allow-Methods', 'POST');
res.setHeader('Access-Control-Allow-Credentials', true);
next();
});
app.use('/user', UserController);
app.use('/data', DataController);
app.get('/', function(req, res){
res.send("Welcome");
});
var https = require('https');
var fs = require('fs');
var options = {
key: fs.readFileSync('key.key'),
cert: fs.readFileSync('cert.crt'),
};
https.createServer(options, function (req, res) {
res.writeHead(200);
res.end("Welcome");
}).listen(3001);
// app.listen(3001, function () {
// console.log('Welcome')
// })

Answer 1

Finally it worked and here is the updated code:
var express = require('express');
var DataController = require('./user/DataController');
var UserController = require('./user/UserController');
var db = require('./database/database-db');
var cors = require('cors');
var app = express();
app.use(cors());
app.use(function(req, res, next) {
res.setHeader("Access-Control-Allow-Origin", "https://www.example.com");
res.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
res.setHeader('Access-Control-Allow-Methods', 'POST');
res.setHeader('Access-Control-Allow-Credentials', true);
next();
});
app.use('/user', UserController);
app.use('/data', DataController);
app.get('/', function(req, res){
res.send("Welcome");
});
// This settings are for HTTPS, SSL web applications
var https = require("https");
var fs = require("fs");
var options = {
key: fs.readFileSync("key.key"),
cert: fs.readFileSync("cert.crt")
};
https.createServer(options,app).listen(3001);
console.log('Welcome')
// // This settings are only for HTTP sites
// var http = require("http");
// var fs = require("fs");
// http.createServer(app).listen(3001);
// console.log('Welcome')

Answer 2

Check ports if there is firewall rules or there's other listing on the the same port