ReactJS Not Found - node.js

Question

The homepage loads ok in my ReactJSAPP, but when I click on any link it throws the following error. Since I am new to ReactJS, I am not sure which file I should check and fix this issue. Nodejs is working on port 4407
Folder Structure
Not Found
404
Error: Not Found
at /home/abc/public_html/ReactNode/app.js:46:13
at Layer.handle [as handle_request] (/home/abc/public_html/ReactNodeNew/node_modules/express/lib/router/layer.js:95:5)
Index.js
var express = require('express');
var router = express.Router();
/* GET home page. */
router.get('/', function(req, res, next) {
res.render('index', { title: 'Express' });
});
module.exports = router;
My package.json is
{
"name": "frontend",
"version": "0.1.0",
"private": true,
"dependencies": {
"bootstrap": "^4.3.1",
"fixed-data-table": "^0.6.4",
"font-awesome": "^4.7.0",
"mysql": "^2.14.1",
"react": "^16.8.6",
"react-bootstrap": "^0.31.5",
"react-dom": "^16.8.6",
"react-redux": "^5.0.6",
"react-router": "^3.0.0",
"react-scripts": "3.0.0",
"redux": "^3.7.2"
},
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test",
"eject": "react-scripts eject"
},
"proxy": "http://localhost:4007",
"eslintConfig": {
"extends": "react-app"
},
"browserslist": {
"production": [
">0.2%",
"not dead",
"not op_mini all"
],
"development": [
"last 1 chrome version",
"last 1 firefox version",
"last 1 safari version"
]
}
}
And 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 index = require('./routes/index');
var users = require('./routes/users');
var app = express();
const port = process.env.PORT || 4007;
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');
var mysql = require("mysql");
//Database connection
app.use(function(req, res, next){
res.locals.connection = mysql.createConnection({
host : '127.0.0.1',
user : 'nodejs',
password : '333365,',
database : 'nodejs',
port : '3306'
});
res.locals.connection.connect();
next();
});
// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__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, 'frontend/build')));
app.use('/api', index);
app.use('/api/users', users);
// catch 404 and forward to error handler
app.use(function(req, res, next) {
var err = new Error('Not Found');
err.status = 404;
next(err);
});
// 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.get('*', (req, res) => {
res.sendFile(path.join(__dirname + '/frontend/build/index.html'))
})
var http = require('http');
module.exports = app;
var server = http.createServer(app);
server.listen(port);