javamail发邮件的奇怪问题

<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="java.util.*,javax.mail.*,javax.mail.internet.*"%><html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>send mail demo</title>
</head><body>
<%
String tto="[email protected]";
String ttitle="标题";
String tcontent="中午好"'Properties props=new Properties();
props.put("mail.smtp.host","smtp.163.com");
props.put("mail.smtp.auth","true");//验证
Session s=Session.getInstance(props);
s.setDebug(true);
MimeMessage message=new MimeMessage(s);//消息对象
InternetAddress from=new InternetAddress("我的雅虎信箱@yahoo.com.cn");
message.setFrom(from);
InternetAddress to=new InternetAddress(tto);
message.setRecipient(Message.RecipientType.TO,to);
message.setSubject(ttitle);
//message.setText(tcontent);
message.setContent(tcontent,"text/html");
message.setSentDate(new Date());
message.saveChanges();
Transport transport=s.getTransport("smtp");
transport.connect("smtp.mail.yahoo.com.cn","我的雅虎信箱","密码");
transport.sendMessage(message,message.getAllRecipients());
transport.close();
%>错误
...
250-AUTH LOGIN PLAIN XYMCOOKIE
250-PIPELINING
250 8BITMIME
DEBUG SMTP: Found extension "AUTH", arg "LOGIN PLAIN XYMCOOKIE"
DEBUG SMTP: Found extension "PIPELINING", arg ""
DEBUG SMTP: Found extension "8BITMIME", arg ""
DEBUG SMTP: Attempt to authenticate
535 authorization failed: only premium users can access this server (#5.7.0)
但是用smtp.163.com服务器和相应的帐号密码时却可以发送
smtp.yahoo.com.cn和公司的邮件服务器却不行