使用nodemailer模块，发送邮件的JS文件为mail.js如下

var nodemailer = require('nodemailer');
var transporter = nodemailer.createTransport({
    service: 'QQ',
    auth: {
        user: '123@qq.com',
        pass: 'XXX'
    }
});
var mailOptions = {
    from: '123@qq.com', // sender address
    to: 'ABC@qq.com', // list of receivers
    subject: 'Hello', // Subject line
    text: 'Hello world', // plaintext body
    html: '<b>Hello world </b>' // html body
};
transporter.sendMail(mailOptions, function(error, info){
    if(error){
        console.log(error);
    }else{
        console.log('Message sent: ' + info.response);
    }
});

QQ邮箱的POP3/IMAP/SMTP/Exchange服务已经开启，node mail.js后报错

{ [Error: connect ETIMEDOUT] code: 'ETIMEDOUT', errno: 'ETIMEDOUT', syscall: 'connect' }

请教这是什么问题？