javax.mail.MessagingException:553 authentication is required

javax.mail.MessagingException:553 authentication is required,smtp2,DNGowLBbuQPU2mFIeZiQBw==.59922S2 1214372564 什么毛病?
我程序代码:
DataInputStream dis = new DataInputStream(request.getInputStream()) ;
String send = dis.readUTF() ;
String subject = dis.readUTF();
String content = dis.readUTF() ;
System.out.println(send+" -- "+subject+" -- "+content);
try {
Properties props = System.getProperties() ;
props.put("mail.smtp.host",host);
Session session = Session.getDefaultInstance(props,new MyAuthenticator()) ;
MimeMessage message = new MimeMessage(session) ;
message.setFrom(new InternetAddress(from)) ;
message.addRecipient(Message.RecipientType.TO,new
InternetAddress(send));
message.setSubject(subject) ;
message.setText(content) ;
Store store = session.getStore("pop3") ;
store.connect("pop3.163.com","****","****");
Transport.send(message) ;
} catch (Exception e) {
e.printStackTrace();
} finally{
dis.close() ;
}