mongodb atlas database not accepting POST request - mongodb

Question

I'm currently trying to teach myself REST APIs through following a tutorial and encountering a problem where after trying to send a POST request through Postman, it reaches an error statement. The API accepts the POST json data as it appears in the terminal using console.log(req.body) so I believe its likely a problem with the mongodb connection.
posts.js file:
const express = require('express');
const router = express.Router();
const Post = require('../models/Post');
router.get('/', (req, res) => {
res.send('It works!');
});
router.get('/', async (req, res) => {
try {
const posts = await Post.find();
res.json(posts);
} catch(err){
console.log("Error 2")
res.status(404).json({message:err});
}
});
router.post('/', async (req, res) => {
const post = new Post({
title: req.body.title,
description: req.body.description
});
try {
const savedPost = await post.save()
res.json(savedPost);
} catch (err) {
console.log(req.body)
console.log("Error encountered when attempting to POST")
res.status(404).json({ message: err });
}
});
module.exports = router;
app.js:
const express = require('express');;
const mongoose = require('mongoose');
const bodyParser = require('body-parser');
require('dotenv/config');
const app = express();
app.use(bodyParser.json());
app.use(express.json());
//import the routes
const postsRoute = require('./routes/posts');
//middleware
app.use('/posts', postsRoute);
//Routes
app.get('/', (req,res) => {
res.send('Welcome to the Home Page');
});
//Connect to DB
mongoose.connect(
process.env.DB_CONNECTION,
{useNewUrlParser:true} ,
() => {console.log('Succesfully connected to DB')
});
//Start server listening
console.log('App is running on: http://localhost:3000');
app.listen(3000);
package.json:
{
"name": "api",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"start": "nodemon app.js"
},
"author": "",
"license": "ISC",
"dependencies": {
"body-parser": "^1.19.2",
"dotenv": "^16.0.0",
"express": "^4.17.3",
"mongoose": "^6.2.9",
"nodemon": "^2.0.15"
}
}
Schema file
const mongoose = require('mongoose');
const PostSchema = mongoose.Schema({
title: {
type: String,
required: true
},
description: {
type: String,
required: true
},
date: {
type: Date,
default: Date.now
}
});
module.exports = mongoose.model('Posts', PostSchema);
console log:
[nodemon] restarting due to changes...
[nodemon] starting `node app.js`
App is running on: http://localhost:3000
Succesfully connected to DB
{ title: 'test', description: 'test2' }
Error encountered when attempting to POST