QQ企业邮箱使用Java代码发送失败，错误DEBUG SMTP: Attempt to authenticate using mechanisms: LOGIN PLAIN DIGEST-MD5 NT

先前使用的代码：

String host = "xxx";
String from = "xxx";
String name = "xx";
String sender = "XXX";
String pwd = XXX";
String port = "465";
Properties prop = new Properties();
 //协议
prop.setProperty("mail.transport.protocol", "smtp");
 //服务器
prop.setProperty("mail.smtp.host", host);
        //端口
        prop.setProperty("mail.smtp.port", port + "");
        //使用smtp身份验证
        prop.setProperty("mail.smtp.auth", "true");
        //使用SSL，企业邮箱必需！
        //开启安全协议
        MailSSLSocketFactory sf = null;
        try {
            sf = new MailSSLSocketFactory();
            sf.setTrustAllHosts(true);
        } catch (GeneralSecurityException e1) {
            e1.printStackTrace();
        }
        prop.put("mail.smtp.ssl.enable", "true");
        prop.put("mail.smtp.ssl.socketFactory", sf);
      Session session = Session.getDefaultInstance(prop, new MyAuthenricator(name, pwd));
        session.setDebug(true);
// 建立邮件消息
MimeMessage mailMessage = new MimeMessage(session);

      Transport.send(mailMessage);

然而却出错了！

DEBUG SMTP: Attempt to authenticate using mechanisms: LOGIN PLAIN DIGEST-MD5 NTLM 
DEBUG SMTP: AUTH LOGIN command trace suppressed
DEBUG SMTP:AUTH LOGIN failed
2017-05-04 16:41:35.589 ERROR com.rbao.east.task.TaskJobImpl - 182 -
sendEmail error mailMessage=javax.mail.internet.MimeMessage@39f840f5
javax.mail.AuthenticationFailedException: 535 Error: authentication failed, system busy

登陆授权失败！

弄了半天，将上述代码开启安全协议改了下：

prop.put("mail.smtp.starttls.enable", "true");
prop.put("mail.smtp.socketFactory.port", port);
prop.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");

最终发送成功了！！！