node.js express routes are not working in remote server - node.js

Question

I am creating a REST api using Node.js And Express, The application works fine including routes and other functanalities on local computer but when uploaded to windows server routes are not working properly, I was able to see Hello World printed on my from home page e.g:- www.abcd.com/,
But when routes are being used eg:- www.abcd.com/users/ it gives 404 - File or directory not found.
Here is my code
server.js
const http = require('http')
const app = require('./app')
const server = http.createServer(app);
server.listen(process.env.PORT, () => {
console.log("Server Started");
});
app.js
const express = require('express');
const morgan = require('morgan');
const bodyParser = require('body-parser');
const app = express();
app.use(morgan('dev'));
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());
app.use((req, res, next) => {
res.header(
'Access-Control-Allow-Origin',
'*'
);
res.header(
"Access-Control-Allow-Headers",
"Origin, X-Requested-with, Content-Type, Accept, Authorization"
);
if (req.method === 'OPTIONS') {
res.header('Access-Control-Allow-Methods', 'PUT, POST, PATCH, DELETE, GET');
return res.status(200).json({});
}
next();
});
const users_routes = require('./api/routes/users.routes');
const message_routes = require('./api/routes/message.routes');
const group_routes = require('./api/routes/group.routes');
const key_routes = require('./api/routes/key.routes');
console.log(users_routes.toString());
app.use('users', users_routes);
app.use('message', message_routes);
app.use('group', group_routes);
app.use('key', key_routes);
app.use('/', (req, res, next) => {
res.writeHead(200, { 'Content-Type': 'text/html' });
res.end('<H1>Hello World!</H1>');
});
module.exports = app;
user.routes.js
const express = require('express');
const router = express.Router();
router.get('/', (req, res, next) => {
Console.log("Hello there");
res.writeHead(200, { 'Content-Type': 'text/html' });
res.end('<H1>Hello World!</H1>');
});
module.exports = router;
Log file after starting app
Server Started
It prints function when used typeof(user_routes)