Heroku MEAN Stack favicon (service not available)

I'm using node.js and trying to deploy my project into Heroku. The system run smoothly without any error on localhost. But when I deployed it, it give these errors on my console:

GET https://caretel.herokuapp.com/ 503 (Service Unavailable)
GET https://caretel.herokuapp.com/favicon.ico 503 (Service Unavailable)

and in my logs:

 /app/node_modules/serve-static/index.js:48
 var opts = Object.create(options || null)
 
 TypeError: Object prototype may only be an Object or null: public
 at Function.serveStatic [as static] (/app/node_modules/serve-static/index.js:48:21)
/* .
   .
   .
   .
*/
2017-05-20T08:02:58.519971+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=caretel.herokuapp.com request_id=de0c339a-1e05-49e0-8d3e-06860b237c44 fwd="183.171.182.30" dyno= connect= service= status=503 bytes= protocol=https

2017-05-20T08:02:59.303711+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=caretel.herokuapp.com request_id=01a6c430-e218-4b70-84e7-58d80d225ac3 fwd="183.171.182.30" dyno= connect= service= status=503 bytes= protocol=https
//...etc....

See full logs: enter image description here

And this is my starting file

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');

var mongoose = require('mongoose');
var passport = require('passport');
require('./config/passport');
//Connect to local db
mongoose.connect('mongodb://localhost/office');

var index = require('./routes/index');
var users = require('./routes/users');
//var products = require('./routes/displays');

var app = express();

//express cors
app.use(function(req, res, next) {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept, Authorization, sid");
  res.header("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE, PUT");
  next();
});

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
  app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
      message: err.message,
      error: err
    });
  });
}

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: {}
  });
});

//code to deploy into heroku
app.set('port', (process.env.PORT || 5000));
//code to deploy into heroku
//app.set('views', __dirname + '/views');
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');

// uncomment after placing your favicon in /public
app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
  extended: false
}));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
//code to deploy into heroku
//app.use(express.static(__dirname + '/public'));

app.use('/', index);
app.use('/users', users);
//app.use('/products', products);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

//code to deploy into heroku
app.get('/', function(request, response) {
  response.render('pages/index');
});

//code to deploy into heroku
app.listen(app.get('port'), function() {
  console.log('Node app js running on port', app.get('port'));
});

//Tried code
/*app.listen(process.env.PORT || 3000, function(){
  console.log("Express server listening on port %d in %s mode", this.address().port, app.settings.env);
});

//Tried code
server.listen(config.port, function () {
  console.log('Express server listening on %d, in %s mode', config.port, app.get('env'));
});

//Tried code
var server_port = process.env.YOUR_PORT || process.env.PORT || 80;
var server_host = process.env.YOUR_HOST || '0.0.0.0';
server.listen(server_port, server_host, function() {
    console.log('Listening on port %d', server_port);
});*/

module.exports = app;

How to solve this? Please give an example base on my codes. Thank you ^_^

*Note, I'm still new to this field. Please make your explanation simple and clearly understandable

via Azinuddin AleleCha