Socket.io is not working , it does not display any error

Question

I am working on a chat application using node.js, socket.io and express. I am using pm2 to run server.js . On the log it says:

0|server   | 18-08 12:14:47.128: Server listening on port 3000

There is no error in console neither. Please bear with me as I am still a newbie in node.js and socket.io. Every help will be highly appreciated. This is my code:

server.js

process.env.NODE_TLS_REJECT_UNAUTHORIZED = "0";
var app = require('express')();
var https = require('https');
var fs = require('fs');
var ssl_server_key = '/data/web/chat/app/node/server_key.pem';
var ssl_server_crt = '/data/web/chat/app/node/server_crt.pem';
var server = https.createServer({
    key: fs.readFileSync(ssl_server_key),
    cert: fs.readFileSync(ssl_server_crt),
    NPNProtocols: ['http/2.0', 'spdy', 'http/1.1', 'http/1.0']
}, app);

var socket = require('socket.io');
var port    = process.env.PORT || 3000;
var io      = socket.listen(server);

server.listen(port, function () {
    console.log('Server listening on port %d', port);
});

io.on('connection', function (socket) {
    console.log('io connected');

    socket.on('new message', function(data){
       io.emit('push message', {msg: data.msg, sendername:data.sendername,     sender:data.sender, receiver: data.receiver,profilepic:data.profilepic,email:data.email,picData:data.picData})        ;
       console.log('new message from ', data.sendername);
     });

    socket.on('new announcement', function(data){
       io.emit('push announcement', {msg: data.msg, title:data.title1,     sendername:data.sendername, profilepic:data.profilepic});

     });
    socket.on('new email', function(data){
       io.emit('push email', {receiver: data.receiver, sender:data.sender,     email:data.email});

     });


    socket.on('disconnect',function(){
        console.log('disconnected');
    });
});

chatnew.js

$(function(){


    var socket = io.connect('https://nd.gcoin.link:3000');

    socket.heartbeatTimeout = 30000;

    console.log('check 1', socket.connected);
    socket.on('connect', function() {
      console.log('check 2', socket.connected);
    });

    socket.on('disconnect', function(){
        console.log('disconnected');
    });

    //var socket = io.connect();
    socket.on('connect', function() {console.log('connect event');});
    socket.on('connect_error', function(err) {console.log('connect     error',err);});

    socket.on('connect_timeout', function(err) {
        console.log("client connect_timeout: ", err);
    });



    socket.on('push message', function(response){
        var sender = $('#sender').val();
        var sender2 = $('#sender2').val();
        var receiver = $('#receiver').val();
        var receiver2 = $('#receiver2').val();
        var sendemail = $('#sendemail').val();
        var email = $('#youremail').val();
        var type = $('#type').val();

        getLastID();

        var last_id = $('#conv_id').val();
            last_id = parseInt(last_id) + 1;

        if(response.profilepic === 'n/a'){
            var pic = '/user_images/no_image.jpg';
        }else if(response.profilepic.substring(0, 4)=== 'https'){
            var pic =response.profilepic;
        }else if(response.profilepic === 'bot'){
            var pic = '/user_images/bot.png';
        }else{
            var pic ='/user_images/'+response.profilepic;
        }

        console.log(response.picData);
        console.log(response.picData.length);

        if(sender == response.sender && response.receiver == receiver2 ){
            updateLastView(response.sender,response.sender,type);
            if(response.picData.length > 6){
            //console.log(response.picData.length);
                $('.chat').append('<li class="self"><div class="float-right"><div class="flex"><label style="" class="self-msg">' +response.msg+'<img src= "/images/uploaded/'+response.picData+'"  class="msg-pic"  onclick="imgEnlarge(this)" /></label><img src="'+pic+'" class="img-profile" onclick="imgEnlarge(this)" ></div><time data-livestamp="'+moment().unix()+'" class="msg-rhs" style="color: #c1c1c1;" ></time></div></li>');

            }else{
                $('.chat').append('<li class="self"><div class="float-right"><div class="flex"><label style="" class="self-msg">' +response.msg+'</label><img src="'+pic+'" class="img-profile" onclick="imgEnlarge(this)" ></div><time data-livestamp="'+moment().unix()+'" class="msg-rhs" style="color: #c1c1c1;" ></time></div></li>');

            }


        }else if(sender == response.receiver && response.sender == receiver2 ){
            updateLastView(response.receiver,response.receiver,type);

            if(response.picData.length > 6){
                $('.chat').append('<li class="other"><div class="float-left"><div class="flex"><img src="'+pic+'" class="img-profile" onclick="imgEnlarge(this)" ><label style="" class="other-msg"> '+response.msg+'<img src= "/images/uploaded/'+response.picData+'" class="msg-pic" onclick="imgEnlarge(this)" /></label></div><time style="color: #c1c1c1;" data-livestamp="'+moment().unix()+'" class="msg-rhs" style="color: #c1c1c1;" ></time></div></li>');

            }else{
                $('.chat').append(' <li class="other"><div class="float-left"><div class="flex"><img src="'+pic+'" class="img-profile"  onclick="imgEnlarge(this)"><label style="" class="other-msg"> '+response.msg+'</label></div><time style="color: #c1c1c1;" data-livestamp="'+moment().unix()+'" class="msg-rhs" style="color: #c1c1c1;"  ></time></div></li>');  

            }


            socket.emit('new email', { receiver: sender, sender: receiver,email:email });

        }


        $("html, body").animate({ scrollTop: $(document).height() }, 1000);



    });




        $(document).on('keyup','.message-box',function(e){
            var message = $('.message-box').val();
            var $this = $(this);
            var len = $(this).val().length;

            //console.log('len:'+len);
            if(len == 0){
                document.getElementById("submit").disabled = false;
                     $("#submit").removeClass('disabled');
            }

            document.getElementById("submit").disabled = false;
             $("#submit").removeClass('disabled');
            // bot(message);

        });

        //image upload
        document.getElementById("file-upload").onchange = function() {
            //document.getElementById("formpic").submit();
            var message = '';
            var sender = $('#sender').val();
            var sendername = $('#sendername').val();
            var receiver = $('#receiver').val();
            var receiver2 = $('#receiver2').val();
            var type = $('#type').val();
            var profilepic = $('#profilepic').val();
            var email = $('#email').val();
            var pic = $("#file-upload").val();
            var pic = pic.replace(/^.*\\/, "");
            var picData = $("#image_data").val();
            var file_data = $('#file-upload').prop('files')[0]; 
            var hash = makehash();
            var filename = hash + '_'+ pic;
            var form_data = new FormData();                  
            form_data.append('file', file_data);
            form_data.append('hash', hash);
            form_data.append('message', message);
            form_data.append('sender', sender);
            form_data.append('receiver', receiver);
            form_data.append('type', type);

            console.log(type);
            console.log(receiver);
            console.log(sender);
            var server_name = $("#server_name").val();
                $('#loading-image').show();
                $.ajax({
                    url: '//'+server_name+'/base__upchat/', 
                    contentType: false,
                    processData: false,
                    data: form_data,                         
                    type: 'post',
                    success: function(x){
                        // alert(x); // display response from the PHP script, if any
                        if(x == 1){
                        socket.emit('new message', { msg: message, sender: sender,sendername:sendername, receiver:receiver2,picData:filename,profilepic:profilepic,email:email });
                        }
                        console.log('success:'+x);
                    },
                    complete: function(){
                        $('#loading-image').hide();

                    }
                 });

                $('#file-upload').val('');

                //updateLastView(sender,sender,type);
                //getLastID();
        };


        // make hash for image upload
        function makehash()
        {
            var text = "";
            var possible =         "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

            for( var i=0; i < 5; i++ )
                text += possible.charAt(Math.floor(Math.random() * possible.length));

            return text;
        }

        // send message
        $('.btn-send').on('click',function(){
            var div = document.getElementById('submit');


            var message = $('.message-box').val();
            var sender = $('#sender').val();
            var sender2 = $('#sender2').val();
            var sendername = $('#sendername').val();
            var receiver = $('#receiver').val();
            var receiver2 = $('#receiver2').val();
            var type = $('#type').val();
            var profilepic = $('#profilepic').val();
            var email = $('#email').val();

            var pic = $("#file-upload").val();
            var pic = pic.replace(/^.*\\/, "");
            var picData = $("#image_data").val();
            var file_data = $('#file-upload').prop('files')[0]; 
            var hash = makehash();
            var filename = hash + '_'+ pic;


        if( message ==''){
            $('.validation').text('不正な文字が入力されました').fadeIn();
            $('#submit').prop('disabled','true').addClass('disabled');
            //$('.send').removeClass('btn-send');
        }else {

            validateWords();
            var check = checkWords(message);

        if (check == true){
            //alert('bad');
            $("#characters").text('不正な文字が入力されました').css('color','red');
            //alert('不正な文字が入力されました');
            $('#submit').prop('disabled','true').addClass('disabled');


        }else{
            document.getElementById("submit").disabled = false;
             $("#submit").removeClass('disabled');
            //console.log('message:'+validateEmail(message));
            if(validateEmail(message) == true ){
                //console.log('message:'+validateEmail(message));
                $("#characters").text('不正な文字が入力されました').css('color','red');
                //alert('不正な文字が入力されました');

                $('#submit').prop('disabled','true').addClass('disabled');

            }else{
                document.getElementById("submit").disabled = false;
                 $("#submit").removeClass('disabled');
                if(phonenumber(message) == true ){
                    $("#characters").text('不正な文字が入力されました').css('color','red');
                    //alert('不正な文字が入力されました');
                    $('#submit').prop('disabled','true').addClass('disabled');

                }else{

                    document.getElementById("submit").disabled = false;
                    $("#submit").removeClass('disabled');


                    $('.message-box').val('');

                    var botdb ='0';
                    updateDB(receiver,sender,message,type,email,botdb); //Update message in DB
                    $('#characters').text('130/130').css('color','#333');
                    socket.emit('new message', { msg: message, sender: sender,sendername:sendername, receiver:receiver2,picData:filename,profilepic:profilepic,email:email });
                    $('.validation').css({"display":"none"});
                    bot(message,receiver,sender,type,email,sendername,receiver2,filename,profilepic,sender2);
                    /* var bot_reply = $("#bot_reply").val();
                     alert(bot2(message));
                    console.log('bot_reply:'+bot_reply);*/
                    //bot(message);
                    /*var bot_reply2 = $("#bot_reply").val();
                    alert(bot_reply2);*/






                }
            }

        }
        }


});


// validating input for email entry
function validateEmail(elementValue)
{   
  // var emailPattern = /^[a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}$/;  
    var emailPattern = /[A-Z0-9._%+-]+@[A-Z0-9.-]+.[A-Z]{2,4}/igm;
    var patt = new RegExp(emailPattern);
   return patt.test(elementValue);   
}  

// validating input for phone number entry
function phonenumber(inputtxt) {

    //var numberPattern = /^\(?([0-9]{3})\)?[-. ]?([0-9]{4})[-. ]?([0-9]{4})$/
    var numberPattern = /\(?([0-9]{3})\)?[-. ]?([0-9]{4})[-. ]?([0-9]{4})/igm;;
    var patt = new RegExp(numberPattern);
   return patt.test(inputtxt);

}


// validating input for bad words entry
 function checkWords(message) {
        var my_textarea = $('.message-box').val().toLowerCase();
        var pattern1 = $('#bad').val();


        var patt = pattern1.split("|");

        if(hasWhiteSpace(my_textarea) == true ){
            var res = my_textarea.split(" ");
            for (i = 0; i < res.length; i++) { 

                for (i2 = 0; i2 < patt.length; i2++) {
                    switch(res[i]){
                    case 'anal':
                    case patt[i2]:
                        return true;
                        break;

                    }
                }

            }

        }else{
            for (i2 = 0; i2 < patt.length; i2++) {
                switch(my_textarea){
                case 'anal':
                case patt[i2]:
                    return true;
                    break;

                }
            }

        }


 }

function hasWhiteSpace(s) {
    return s.indexOf(' ') >= 0;
}



 //inserting message to db
 function updateDB(receiver,name,msg,type,email,botdb){
     console.log('receiver:' + receiver);
     console.log('name:' + name);
     console.log('msg:' + msg);
     console.log('type:' + type);
     console.log('email:' + email);
     console.log('botdb:' + botdb);
        $.post('/base__process/',{method:'update',receiver:receiver,sender:name,msg:msg,type:type,email:email,botdb:botdb},function(response){
            // alert(response);
            var pic1 = JSON.parse(response);
            //$('.uspoints').text(number_format(pic1.pt,'.','.',',')+' PTS.');
            console.log('response:' + response);
        });
 }

 function bot(msg,receiver,sender,type,email,sendername,receiver2,filename,profilepic,sender2){

     var type ='0';
     var botdb ='1';
     $.post('/base__process/',{method:'bot_reply',msg:msg},function(reps){

         console.log('bot:'+reps);
            var dt = JSON.parse(reps);
            console.log('msg: '+msg);
             console.log('botrep:'+dt.reply);
             console.log('botmsg:'+dt.msg);
            if(dt.msg == msg){
                 $("#bot_reply").val(dt.reply);
                /* var rep = dt.rep;
                 return rep;*/
                // alert( $("#bot_reply").val());
                 var bot_reply = $("#bot_reply").val();
                 if(bot_reply != 'n/a'){

                        updateDB(sender2,receiver2,bot_reply,type,email,botdb); //Update message in DB
                        $('#characters').text('130/130').css('color','#333');
                        socket.emit('new message', { msg: bot_reply, sender: receiver2,sendername:sendername, receiver:sender,picData:filename,profilepic:'bot',email:email });
                        $('.validation').css({"display":"none"});
                    }

             }else{
                 $("#bot_reply").val('n/a');
                /*var rep = 'n/a';
                 return rep;*/
                // alert( $("#bot_reply").val());
             }


    });


 }


 function number_format (number, decimals, dec_point, thousands_sep) {
        // Strip all characters but numerical ones.
        number = (number + '').replace(/[^0-9+\-Ee.]/g, '');
        var n = !isFinite(+number) ? 0 : +number,
            prec = !isFinite(+decimals) ? 0 : Math.abs(decimals),
            sep = (typeof thousands_sep === 'undefined') ? ',' : thousands_sep,
            dec = (typeof dec_point === 'undefined') ? '.' : dec_point,
            s = '',
            toFixedFix = function (n, prec) {
                var k = Math.pow(10, prec);
                return '' + Math.round(n * k) / k;
            };
        // Fix for IE parseFloat(0.55).toFixed(0) = 0;
        s = (prec ? toFixedFix(n, prec) : '' + Math.round(n)).split('.');
        if (s[0].length > 3) {
            s[0] = s[0].replace(/\B(?=(?:\d{3})+(?!\d))/g, sep);
        }
        if ((s[1] || '').length < prec) {
            s[1] = s[1] || '';
            s[1] += new Array(prec - s[1].length + 1).join('0');
        }
        return s.join(dec);
    }

 // fetching bad words
 function validateWords()
 {   

    $.post('/base__process/',{method:'validateWords'},function(reps){
                  $("#bad").val(reps);
                 // console.log(reps);
            });

 }  

 // updating message last view
 function updateLastView(sender,receiver,type){

        $.post('/base__process/',{method:'updateLastView',sender:sender,receiver:receiver,type:type},function(response){

            var pic1 = JSON.parse(response);
        });
  }


//getting last insert id in message
function getLastID(){

    $.post('/base__process/',{method:'getLastID'},function(response){           
        var pic1 = JSON.parse(response);
        console.log('last:'+pic1.conv_id);
          $('#conv_id').attr('value', pic1.conv_id);
    });

}




});

$(function() {

//Pretty Photo
$("a[rel^='prettyPhoto']").prettyPhoto({
    social_tools: false
}); 

$('#input').keypress(function(event) {
    if (event.keyCode == 13) {
        event.preventDefault();
    }
});

$('#input').keyup(updateCount);
$('#input').keydown(updateCount);

function updateCount() {
    var cs = $(this).val().length;
    var cs2 = 130 - cs;
    var cs3 =  130 - cs+'/130';
    if(cs2 <= 5){
      $('#characters').text(cs3).css('color','red');
    }else{
      $('#characters').text(cs3).css('color','#333');
    }

}

function maxLength(el) {    
    if (!('maxLength' in el)) {
        var max = el.attributes.maxLength.value;
        el.onkeypress = function () {
            if (this.value.length >= max) return false;
        };
    }
}

maxLength(document.getElementById("input"));





});

Edit1: tried the following but no luck

Socket.io not starting

Node.js Socket.IO not working completely

Edit 2: this error show :

connect error Error: xhr poll error
Stack trace:
[14]</n.prototype.onError@https://gcoin.link/js/socket.io.js:719:25
[17]</</o.prototype.doPoll/<@https://gcoin.link/js/socket.io.js:885:25
[9]</n.prototype.emit@https://gcoin.link/js/socket.io.js:419:63
[17]</</i.prototype.onError@https://gcoin.link/js/socket.io.js:921:21
[17]        </</i.prototype.create/e.onreadystatechange/<@https://gcoin.link/js/socket.io.js:907:33

after adding this :

socket.on('connect_error', function(err) {console.log('connect error',err);});

tried these:

How configure reconnecting in socket.io?

Controlling the heartbeat timeout from the client in socket.io

but error : connect error Error: xhr poll error still shows

These scripts are loaded to ch002.html

<script src="/js/chatnew.js" ></script>
<script src="/js/socket.io.js"></script>