Error: Operation `bootcamps.insertOne()` buffering timed out after 10000ms

I am having an issue inserting a document into MongoDB. I am able to successfully connect to the database, but when i try to insert a new document i get the following error:

Error: Operation `bootcamps.insertOne()` buffering timed out after 10000ms
[nodemon] app crashed - waiting for file changes before starting...

URI Connection string:

MONGO_URI=mongodb+srv://blahblah:<password>@cluster0.ohppr.mongodb.net/devcamper?retryWrites=true&w=majority&appName=Cluster0

db.js

const mongoose = require('mongoose')

const connectDB = async () => {
  const conn = await mongoose.connect(process.env.MONGO_URI)

  console.log(`MongoDB Connected: ${conn.connection.host}`.cyan.underline.bold)
}

module.exports = connectDB

MongoDB Network:

server.js

const express = require('express')
const dotenv = require('dotenv')
const connectDB = require('./config/db')

// Load env variables.
dotenv.config({ path: './config/config.env' })

// Connect to DB
connectDB()

bootcamp.js

const Bootcamp = require('../models/Bootcamps')

// @desc    Create new bootcamp
// @route   POST /api/v1/bootcamps
// @access  Private
exports.createBootcamp = async (req, res, next) => {
  //console.log(req.body)
  //res.status(201).json({success: true})
  const bootcamp = await Bootcamp.create(req.body);
  res.status(201).json({
  sucess: true,
  data: bootcamp
  })
}

if i comment out the following lines of code everything runs ok.

const bootcamp = await Bootcamp.create(req.body);
  res.status(201).json({
  sucess: true,
  data: bootcamp
  })
}

Postman