500 callback error with passport-windowslive - node.js

Question

[FIXED]:
in my code, i was missing
passport.serializeUser(function(user, done) {
done(null, user);
});
passport.deserializeUser(function(obj, done) {
done(null, obj);
});
i am writing an demo app to access microsoft one-drive
when i visit http://localhost:3000/auth/mslive, my app will redirect me to single-sign-on with windows-live
however, callback function in "/mslive" and "/mslive/callback" never get hit.
and I keep getting 500 error when windows live try to re-direct back to my app.
any idea?
Remote Address:127.0.0.1:3000
Request URL:http://anotherdemoapp.localtest.me:3000/auth/mslive/callback?code=d3f9d642-b013-af4e-e4d0-0cb828554ca5
Request Method:GET
Status Code:500 Internal Server Error
app.js
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 routes = require('./routes/index');
var authRoutes = require("./routes/auth");
var app = express();
//// 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(__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')));
app.use('/', routes);
app.use("/auth", authRoutes);
auth.js
var express = require('express');
var path = require("path");
var passport = require("passport");
var passportMSLive = require("passport-windowslive");
var app = express();
app.use(passport.initialize());
passport.use(new passportMSLive.Strategy({
clientID: process.env.MSLiveClientID,
clientSecret: process.env.MSLiveClientSecret,
callbackURL: "http://anotherdemoapp.localtest.me:3000/auth/mslive/callback"
},
function (accessToken, refreshToken, profile, done) {
// this callback function will be invoked after successfully login
return done(null, profile);
}
));
// call back
app.get(
"/mslive",
passport.authenticate("windowslive", {
scope: ["wl.offline_access", "wl.contacts_skydrive", "wl.skydrive", "wl.skydrive_update", "wl.signin"]
}),
function (req, res) {
// never enter here
res.send("mslive login");
}
);
app.get(
"/mslive/callback",
passport.authenticate("windowslive", {
failureRedirect: '/mslive/fail'
}),
function (req, res) {
// never enter here
res.send("mslive callback");
}
);
app.get("/mslive/fail", function (req, res) {
// never enter here
res.send("login failed");
});
module.exports = app;