Nodemailer：无法通过Gmail帐户发送电子邮件

Question

POST /reset_password的全部代码

router.post('/reset_password',function(req,res,next){
  // From a random token
  async.waterfall([
    function(done) {
      crypto.randomBytes(20, function(err, buf) {
        var token = buf.toString('hex');
        // works well
        console.log(token);
        done(err, token);
      });
    },
    function(token, done) {
      Account.findOne({ email: req.body.email }, function(err, user) {
        if (!user) {
          console.log('No email found')
          return res.redirect('/reset_password');
        }
        user.resetPasswordToken = token;
        // link will be expired in 20 minutes
        user.resetPasswordExpires = Date.now() + 1200000;
        user.save(function(err) {
          done(err, token, user);
        });
      });
    },
    function(token, user, done) {
      var transport = nodemailer.createTransport(smtpTransport({
        service: 'Gmail',
        auth: {
            xoauth2: xoauth2.createXOAuth2Generator({
            user: 'my_email@gmail.com',
            pass: 'my_password'
          })
        }
      }));
      var mailOptions = {
        to: user.email,
        from: 'my_email@gmail.com',
        subject: 'Link to reset your password - Behavior Recording',
        text: 'You are receiving this because you (or someone else) have requested the reset of the password for your account.\n\n' +
          'Please click on the following link, or paste this into your browser to complete the process:\n\n' +
          'http://' + req.headers.host + '/reset/' + token + '\n\n' +
          'If you did not request this, please ignore this email and your password will remain unchanged.\n'
      };
      transport.sendMail(mailOptions, function(err) {
        console.log('An e-mail has been sent to ' + user.email + ' with further instructions.');
        res.redirect('/');
        done(err, 'done');
      });
    }
  ], function(err) {
    if (err) return next(err);
    console.log('error happend')
    res.redirect('reset_password');
  })
});

我的代码中存在两个问题：

问题

      transport.sendMail(mailOptions, function(err) {
        console.log('An e-mail has been sent to ' + user.email + ' with further instructions.');
        res.redirect('/');
        done(err, 'done');
      }

出现500错误：POST /reset_password 500 1849.227 ms - 30 对console.log进行调试，此功能上方的所有代码均有效。

控制台打印An e-mail has been sent to useremail@gmail.com with further instructions.，res.redirect('/')存在

因此错误似乎发生在done(err, 'done');中，但是作为新的node.js用户，我不知道如何在不删除此行的情况下进行修复。

问题b

我已经将我的Google帐户（用于发送电子邮件的帐户）设置为允许安全性较低的应用，但是我无法通过注册用户帐户（用于接收电子邮件的邮件）接收电子邮件

>

xoauth2 也在上面的代码中的我的身份验证配置中（这是其他类似的“无法通过Google帐户发送电子邮件”问题的解决方案），但仍然不起作用

user.email存在并且正确