Nodemailer with Gmail service not working on heroku

Question

I've got a basic email setup done for sending an email using Nodemailer with AngularJS and NodeJS and I've got the project deployed on heroku.

The emailing seems to be working just fine when I am running the app on heroku, but when I get it deployed to Heroku no emails are sent.

For authentication, I am using a Gmail address and I also have a bcc to another Gmail address. So from and bcc addresses are two different Gmail addresses. The from address is the same as the address used for authentication.

Could somebody help me with resolving this issue?

Edit: Adding code

var nodemailer = require('nodemailer');
var transporter = nodemailer.createTransport({
    service: 'Gmail',
    auth: {
        user: '[email protected]',
        pass: 'foobar'
    }
});

router.post('/send',function(req,res){

    var mailOptions = {
        from: 'Foo Bar ✔ <[email protected]>',
        to: req.body.email,
        subject: "Hello " + req.body.email,
        text: 'Hello ' + req.body.email + '✔',
        html: "<p>Hello " + req.body.email + " </p>",
        bcc: "[email protected]"
    };
    transporter.sendMail(mailOptions, function(error, info){
        if(error){
            console.log(error);
        }else{
            console.log('Message sent: ' + info.response);
            res.send(200);
        }
    });        
});

Answer 1

I believe this is an issue with google account security.

• Google blocked your sign-in to use the mailing features due to an unknown device (location).

A few step to verify this:

• Start your server locally and sends the email.

• Check your account alerts for unknown sign-in.

This can be temporally resolved by: https://accounts.google.com/DisplayUnlockCaptcha

A more permanent resolution would be to change your password to a stronger level:

upper case letter + lower case letter + special symbols + numbers

Answer 2

Instead of using direct gmail credentials like this

auth: {
    user: '[email protected]',
    pass: 'foobar'
}

Use OAuth2

 auth: {
    type: 'OAuth2',
    user: '[email protected]',
    accessToken: 'ya29.Xx_XX0xxxxx-xX0X0XxXXxXxXXXxX0x'
}

Google blocks the heroku IPs (unsafe), if we are using direct credentials like you mentioned above. You can refer this Medium article here