Esta es mi configuraciónController:

var sendSmtpMail = function (req,res) {
  var transport = nodemailer.createTransport({
  service:'gmail',
   auth: {
             user: "[email protected]",
             pass: "qwerr@wee"
        }
   });
   var mailOptions = {
        from: "[email protected]", 
        to:'[email protected]', 
        subject: req.body.subject+"nodejs working ?", 
        text: "Hello world ?",  
    }
    transport.sendMail(mailOptions, function(error, response){
      if(error){
         res.send("Email could not sent due to error: "+error);
         console.log('Error');
       }else{
         res.send("Email has been sent successfully");
         console.log('mail sent');
      } 
  }); 

en cartero recibí el error así:

No se pudo enviar el correo electrónico debido a un error:

Error: Invalid login: 535-5.7.8 Username and Password not accepted. Learn more at 535 5.7.8  https://support.google.com/mail/?p=BadCredentials g7sm64435626pfj.29 - gsmtp