Node.js & Express web API not working on azure

I have created a basic app with React SPA and Node.js & Express web API using this sample
https://github.com/Azure-Samples/ms-identity-javascript-react-tutorial/tree/main/5-AccessControl/1-call-api-roles

The app is running fine locally- both front-end authentication and backend API calls are working as expected.

When I deploy the app on Azure, the front end is working fine but the backend API calls are not working at all and they timeout- I do not see any logs in the backend either. While locally, I can see all the console.logs on invoking the API calls.

I have tried many changes to troubleshoot Node.js app mentioned below and I am seeking guidance on what other settings/ changes might help to get the Node.js app running on Azure.

• I tried to run the backend manually in Azure as well in /wwwroot/server – node app.js and I see the log saying API is listening, but API calls timeout.

• The web.config.js is pointing to server/app.js

• On Azure, the React app successfully runs only on port 443 as below and doesn’t run at all when set to some other PORT:

client/package.json

...
"scripts": {
    "start": "set PORT=443&& react-scripts start",
...

Locally it runs on all the ports when specified as below:

client/package.json

...
"scripts": {
    "start": "set HTTPS=true&&set SSL_CRT_FILE=certificate.crt&&set SSL_KEY_FILE=privateKey.key&&set PORT=3000&& react-scripts start",
...

• fetch calls timeout on Azure

client/fetch.js


export const getTest = async (env) => {
    // const accessToken = await getToken();

    const headers = new Headers();
    // const bearer = `Bearer ${accessToken}`;

    // headers.append("Authorization", bearer);

    const options = {
        method: "GET",
        headers: headers,
    };

    return fetch(protectedResources.apiList.test, options)
        .then(response => response.json())
        .catch(error => console.log(error));
}

• In server/app.js, locally, both commenting out and using the authentication logic works for API calls, but none works on Azure.
• Also tried to run Node.js on both http and https. PS. locally only HTTPS works for both client and Node as redirectUri is https

server/app.js


const path = require('path');
const express = require("express");
const cors = require("cors");
const axios = require("axios");
const PORT = process.env.PORT || 8080;
require("dotenv").config();
const app = express();
app.use(cors());
app.use(express.json());

//app.use(express.static(path.resolve(__dirname, '../client/build')));

app.get("/api/test", (req, res) => {
  res.json("hi");
});

//...other bearer token code

// https.createServer(httpsOptions, app).listen(PORT, () => console.log(`Server is running on port ${PORT}`));

app.listen(PORT, () => console.log(`Server is running on port ${PORT}`));