Integrating OKTA into Existing AD app - NodeJS ExpressOIDC

Questions
1

I currently use Active Directory (using the middleware activedirectory2) with passport to allow users to login. We are slowly moving everything in our company over to OKTA SSO; in the meantime I will have to allow for login with both OKTA and Active Directory (for now let’s just get OKTA to work). I have the example apps working on our OKTA dev environment (so I know the App Settings are correct) and am trying to integrate it to my application, but am running into a problem.

After initializing OKTA, I get the custom login screen but after I enter the UN/ PW I get the following Error message:

Cannot POST /login

Here is my code

var express = require('express');
var app = express();

const asyncConfig = require('config/async').asyncConfig;
const getSecret = require('../lib/secretManager');
var session = require('express-session');

app.use(session({
	secret: asyncConfig(getSecret('session-secret')),
	proxy: true,
	resave: true,
	saveUninitialized: true
}));

const { ExpressOIDC } = require('@okta/oidc-middleware');
const oktaConfig = require('./config/okta.env');
const oidc = new ExpressOIDC({
	issuer: oktaConfig.ISSUER,
	client_id: oktaConfig.CLIENT_ID,
	client_secret: oktaConfig.CLIENT_SECRET,
	appBaseUrl: oktaConfig.APP_BASE_URL,
	scope: oktaConfig.SCOPE,
	routes: {
		login: {
			path: '/oktaLogin',
			viewHandler: (req, res, next) => {
				const fullURL = new URL(oktaConfig.ISSUER);
				const baseUrl = fullURL.protocol + '//' + fullURL.host;
				var token = req.csrfToken();
				res.cookie('XSRF-TOKEN', token);
				res.locals.csrfToken = token;
				console.dir('View Handler')
				res.render(path.join(__dirname, './subapps/login/views/oktaLogin'), {
					req: req,
					csrfToken: token,
					baseUrl: baseUrl
				});
			}
		},
		callback: {
			path: '/authorization-code/callback',
			handler: (req, res, next) => {
				console.dir('Success callback')
			},
			defaultRedirect: '/'
		}
	}
});

app.use(oidc.router);


function addUserContext(req, res, next) {
	if (!req.userContext) {
		return next();
	}	
	req.locals.user.name = req.userContext.userinfo.name;
	req.locals.user.groups = req.userContext.userinfo.groups;
	next();
}

app.use(addUserContext);

require('./routes/public')(app, oidc.router);

require('./routes/private')(app); // <- I will ensure authenticated here

module.exports = {app, oidc};

Then in my routes/public I have the following:

var loginRouter = require('../subapps/login/routes/index');
var healthcheckRouter = require('../subapps/healthcheck/routes/healthcheck');
module.exports = function(app, oidcRouter){
	app.get('/', (req, res, next) => {
		console.dir('public')
		if (req.userContext) {
			next()
		} else {
			res.redirect('/OGLogin');
		}
	});
	app.use('/login', oidcRouter);
	app.use('/authorization-code/callback', (req, res, next) => {
		console.dir('Public callback')
	})
	app.use('/OGLogin', loginRouter);
	app.use('/healthcheck', healthcheckRouter);
};

Even though I tried in both place (and each separately) I cannot get the POST to /login to work.