router.get('/sendEmail', (req, res) => {

  var smtpConfig = {
      host: 'smtp.gmail.com',
      port: 465,
      secure: true,
      auth: {
          user: 'hamza.haddad.dev@gmail.com',
          pass: 'mypass'
      }
  };

  var transporter = nodemailer.createTransport(smtpConfig);

  var mailOptions = {
      from: 'hamza.haddad.dev@gmail.com',
      to: 'hamzavelizy@gmail.com',
      subject: 'Test',
      text: 'test'
  };

  transporter.sendMail(mailOptions, function(error, info){
      if(error){
          return console.log(error);
      }
      console.log('Message sent: ' + info.response);
  });
});

{ Error: Invalid login: 534-5.7.14 <https://accounts.google.com/signin/continue?sarp=1&scc=1&plt=AKgnsbv_
534-5.7.14 zR7mnH8igWdTeU9EPAHvZ_YlSTc0tUfckCSqFu09AaumeVPdDxTia6h8O4z6I3hXEDFzc1
534-5.7.14 hqH-V6TX7hiIkyuB2oQRORqiIC5_P2DUbwEjaR9wKzT44RJynX5cSpFZaNkSQZdz1nQ0vS
534-5.7.14 xKU0GHv_LpkjhZ4DDx-M75rAccsGH-FZDcdB1Dl1YvTO68rijSiLE6CRe3QfdalesmVWpc
534-5.7.14 krt1RPvYF4ql8j3Ty5bkxix30Z7ZI> Please log in via your web browser and
534-5.7.14 then try again.
534-5.7.14  Learn more at
534 5.7.14  https://support.google.com/mail/answer/78754 y6sm6163530wrg.48 - gsmtp
    at SMTPConnection._formatError (/home/haddad/projects/portfolio/server/portfolioserveur/node_modules/nodemailer/lib/smtp-connection/index.js:557:19)
    at SMTPConnection._actionAUTHComplete (/home/haddad/projects/portfolio/server/portfolioserveur/node_modules/nodemailer/lib/smtp-connection/index.js:1253:34)
    at SMTPConnection._responseActions.push.str (/home/haddad/projects/portfolio/server/portfolioserveur/node_modules/nodemailer/lib/smtp-connection/index.js:340:26)
    at SMTPConnection._processResponse (/home/haddad/projects/portfolio/server/portfolioserveur/node_modules/nodemailer/lib/smtp-connection/index.js:706:20)
    at SMTPConnection._onData (/home/haddad/projects/portfolio/server/portfolioserveur/node_modules/nodemailer/lib/smtp-connection/index.js:509:14)
    at TLSSocket._socket.on.chunk (/home/haddad/projects/portfolio/server/portfolioserveur/node_modules/nodemailer/lib/smtp-connection/index.js:461:47)
    at emitOne (events.js:96:13)
    at TLSSocket.emit (events.js:191:7)
    at readableAddChunk (_stream_readable.js:176:18)
    at TLSSocket.Readable.push (_stream_readable.js:134:10)
  code: 'EAUTH',
  response: '534-5.7.14 <https://accounts.google.com/signin/continue?sarp=1&scc=1&plt=AKgnsbv_n534-5.7.14 zR7mnH8igWdTeU9EPAHvZ_YlSTc0tUfckCSqFu09AaumeVPdDxTia6h8O4z6I3hXEDFzc1n534-5.7.14 hqH-V6TX7hiIkyuB2oQRORqiIC5_P2DUbwEjaR9wKzT44RJynX5cSpFZaNkSQZdz1nQ0vSn534-5.7.14 xKU0GHv_LpkjhZ4DDx-M75rAccsGH-FZDcdB1Dl1YvTO68rijSiLE6CRe3QfdalesmVWpcn534-5.7.14 krt1RPvYF4ql8j3Ty5bkxix30Z7ZI> Please log in via your web browser andn534-5.7.14 then try again.n534-5.7.14  Learn more atn534 5.7.14  https://support.google.com/mail/answer/78754 y6sm6163530wrg.48 - gsmtp',
  responseCode: 534,
  command: 'AUTH PLAIN' }