passport-saml - express - redirected url not submi

Below is the error that I am getting on my console today as opposed to yesterday when the same code was working fine.

Error: SAML assertion not yet valid
        at SAML.checkTimestampsValidityError

I have verified that I receive a success from the IDP and hence the application gets redirected to the '/home' endpoint in the URL which has been mentioned in the config file.

Additionally, when I submit the form, after an auto redirection [which shows me Internal Server Error]

I press refresh button of the browser and a form submission happens and the expected result is achieved.

My problem is, why doesn't this happens automatically or how and where can I do this submission programatically.

passport.js

const SamlStrategy = require('passport-saml').Strategy;

module.exports = function (passport, config) {

  passport.serializeUser(function (user, done) {
    done(null, user);
  });

  passport.deserializeUser(function (user, done) {
    done(null, user);
  });

  passport.use(new SamlStrategy(
    {
      entryPoint: config.passport.saml.entryPoint,
      issuer: config.passport.saml.issuer,
      cert: config.passport.saml.cert,
      path: config.passport.saml.path,
      identifierFormat: config.passport.saml.identifierFormat
    },
    function (profile, done) {

      debugger;
      return done(null,
        {
          sessionIndex: profile.sessionIndex,
          nameID: profile.nameID,
          lastName: profile.lastName,
          firstName: profile.firstName,
          gid: profile.gid,
          county: profile.county,
          mail: profile.mail,
          companyUnit: profile.companyUnit,
          preferredLanguage: profile.preferredLanguage,
          orgCode: profile.orgCode,
          email: profile.email
        });
    })
  );

};

config.js

module.exports = {
      passport: {
        strategy: 'saml',
        saml: {
          callbackUrl: '/home',
          path: '/home',
          entryPoint: 'https://.../GetAccess/Saml/IDP/SSO/Unsolicited?GA_SAML_SP=APP',
          issuer: '...',
          cert: '...',
          identifierFormat: null
        }
      }
  };

app.js

import express from 'express';
import helmet from 'helmet';
import cookieParser from 'cookie-parser';
import bodyparser from 'body-parser';
import path from 'path';
import logger from 'morgan';
import cors from 'cors';
import passport from 'passport';
import session from 'cookie-session';

const config = require('./config.js');
require('./passport')(passport, config);
var app = express();
app.use(logger('dev'));
app.use(cookieParser());
app.use(bodyparser.json());
app.use(bodyparser.urlencoded({ extended: false }));
app.use('/public', express.static(path.join(__dirname, '../public')));
app.use('/data', express.static(path.join(__dirname, '../uploads/')));
app.use(session(
  {
    resave: true,
    saveUninitialized: true,
    secret: 'secret value'
  }));
app.use(passport.initialize());
app.use(passport.session());
app.use(helmet());
app.use(cors());

require('../router/routeConfig')(app, config, passport);

module.exports = app;

routeConfig.js

module.exports = function (app, config, passport) {


  app.get('/', passport.authenticate(config.passport.strategy, {
    successRedirect: '/home',
    failureRedirect: 'https://.../GetAccess/Saml/IDP/SSO/Unsolicited?GA_SAML_SP=APP'
  }));

  app.get('/app', passport.authenticate(config.passport.strategy, {
    successRedirect: '/home',
    failureRedirect: 'https://.../GetAccess/Saml/IDP/SSO/Unsolicited?GA_SAML_SP=APP'
  }));

  app.post(config.passport.saml.path,
    passport.authenticate(config.passport.strategy,
      {
        failureRedirect: 'https://.../GetAccess/Saml/IDP/SSO/Unsolicited?GA_SAML_SP=APP',
        failureFlash: true
      }),
    function (req, res) {
      debugger;
      res.sendFile(path.join(__dirname, "../public/index.html"));
    });

};

Finally I have figured this out after some research,

As we understand that there are two parties involved in the SAML Authentication Process i.e. IDP and SP, therefore there are certain conditions between these which are supposed to be met, as part of the contract. One such condition is the TIME.

<saml:Conditions NotBefore="2019-08-01T11:02:49Z" NotOnOrAfter="2019-08-01T11:03:59Z">

This is a tag that I have clipped from the saml response received from the IDP, here the time of my(SP's) server should be between NotBefore and NotOnOrAfter during the process of authentication.

Therefore, I need to calibrate the clock of my server by a few seconds so that I fit in the time-slice of NotBefore and NotOnOrAfter of the server.

Of course that is not the way this should be done, but some +n or -n minutes should be allowed from the IDP side (importantly both SP and IDP to follow UTC times).