var nodemailer = require("nodemailer");

var transporter = nodemailer.createTransport({
 host: 'smtp.gmail.com',
 port: 465,
 secure: true, // use SSL
 auth: {
    user: 'abc@gmail.com',
    pass: '*******'
 }
});

var mailOptions = {
 from: "abc@gmail.com",
 to: "def@gmail.com",
 subject: "Hello",
 generateTextFromHTML: true,
 html: '<p>Your html here</p>'
};

transporter.sendMail(mailOptions, function(error, response) {
  if (error) {
    console.log(error);
  } else {
    console.log(response);
  }
transporter.close();
});

{ Error: Connection timeout
at SMTPConnection._formatError (/root/mail/node_modules/nodemailer/lib/smtp-connection/index.js:591:19)
at SMTPConnection._onError (/root/mail/node_modules/nodemailer/lib/smtp-connection/index.js:564:20)
at Timeout._connectionTimeout.setTimeout (/root/mail/node_modules/nodemailer/lib/smtp-connection/index.js:256:18)
at ontimeout (timers.js:386:14)
at tryOnTimeout (timers.js:250:5)
at Timer.listOnTimeout (timers.js:214:5) code: 'ETIMEDOUT', command: 'CONN' }