Error: connect ETIMEDOUT 65.55.176.126:587 - nodemailer with hotmail

I came across this issue when trying to send a basic test email in my expressJS app. After some research it became apparent that the issue was being caused by Gmail and not nodemailer itself, and that changing to a different service would fix the problem. However, after changing to hotmail I am still getting the same error? Can anybody provide some insight?

emailService.js :

const nodemailer = require('nodemailer');

// create reusable transporter object using the default SMTP transport
var transporter = nodemailer.createTransport({
    service: 'hotmail',
    auth: {
        user: '****@outlook.com',
        pass: '****'
    }
});

// setup email data with unicode symbols
var mailOptions = {
    from: '****@outlook.com', // sender address
    to: '****@hotmail.co.uk', // list of receivers
    subject: 'Test Email', // Subject line
    text: 'Hello world ?' // plain text body
};

module.exports = {

    sendTestEmail: function() {
        transporter.sendMail(mailOptions, function(error, info) {
            if(error){
                console.log('error sending email: ' + error);
            } else {
                console.log('email sent' + info.response);
            }
        });
    }
};

Then I am simply calling this function within the GET function of one of my pages like so:

router.get('/', function (req, res) {

    //Do some stuff

    emailService.sendTestEmail();

    //Do more stuff
});

Error: error sending email: Error: connect ETIMEDOUT 65.55.176.126:587

Many thanks!

via C Grant