Unable to access any of my routes when deployed to heroku...working fine on localhost

[pardeepgoyal07]

here is my code for index.js :-
const express = require('express')
require('./db/mongoose')
const userRouter = require('../src/routers/userRouter')
const taskRouter = require('../src/routers/taskRouter')
const app = express()
const port = process.env.PORT
// app.use((req,res,next)=>
// {
// res.status(503).send('App under maintainance')
// })
app.use(express.json())
app.use(userRouter)
app.use(taskRouter)
app.listen(port,()=>{
console.log('Server is up and running on port ',port)
})

For userRouter :-
const express = require('express')
const User = require('../models/user-model')
const router = new express.Router()
const { deletemsg } = require('../../email/deletemsg')
const {welcomeEmail} = require('../../email/account')
const sharp = require('sharp')
const auth = require('../middleware/auth')
const multer = require('multer')
router.post('/users',async (req,res)=>{
const user = new User(req.body)
try{
await user.save()
welcomeEmail(user.email,user.name)
const token = await user.generatejwt()
res.status(201).send({user,token})
}catch(e){
res.status(404).send()
}
})
router.post('/users/login',async (req,res)=>
{
const user = await User.findbyCredentials(req.body.email,req.body.password)
const token = await user.generatejwt()
if(!user)
{
return res.status(400).send('Unable to login')
}
res.status(200).send({user,token})
})

[irhamputra]

have you looked into Heroku Logs?