authenticate tp express server tunneled through ngrok - express

Question

I have an express server serving react pages. I am trying to show the work to a client via a ngrok tunnel. But whenever I try to log in at the ngrok URL for my server it fails to connect back to my localhost where the express routes for auth are.
I feel like it's a simple error I'm making. The browser is trying to make a request to the express server at localhost:5000, but there is nothing at localhost on my client's network.
This is my app.js
const createError = require('http-errors');
const express = require('express');
const debug = require('debug')('app');
const cookieParser = require('cookie-parser');
const logger = require('morgan');
require('dotenv').config()
const ensureToken = require('./middleware/ensureToken');
const path = require('path');
const app = express();
const { init } = require('./utils/cron/createCron');
const cors = require('cors')
// Routers
const authRouter = require('./routes/auth')
const botRouter = require('./routes/bot')
const proxyRouter = require('./routes/proxy');
const winstonLogger = require('./utils/log/logger');
app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
const whiteList = ['http://localhost:3000/', 'http://localhost:3000']
const corsOptions = {
origin: (origin, callback)=>{
if (whiteList.indexOf(origin) !== -1){
callback(null, true)
}else{
callback(new Error('Not Allowed by CORS'))
}
optionsSuccessStatus:200
}
}
// app.use(cors(corsOptions))
app.use(cors({ credentials: true, origin: true }))
app.use(express.static(path.join(__dirname, 'build')));
// Base Routes
app.use('/api/auth', authRouter);
app.use(ensureToken) //Add this before routes that need to be protected ny valid token
app.use('/api/bot', botRouter);
app.use('/api/proxy', proxyRouter);
app.get("*", (req, res) => {
res.sendFile(path.join(__dirname, "../client/build/index.html"));
});
// catch 404 and forward to error handler
app.use(function(req, res, next) {
next(createError(404));
});
// 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');
});
app.listen(process.env.PORT, ()=>{
winstonLogger.info(`Listening on ${process.env.PORT}`)
debug(`Listening on ${process.env.PORT}`);
console.log(`Listening on ${process.env.PORT}`);
init()
})
module.exports = app;
Any help is appreciated!!