email-phpmailer发送邮件提示SMTPservererror怎么回事？

以下是我的代码
错误提示信息为：
SMTP server error: Error: send HELO/EHLO first
如果把SMTPAuth改为true，错误为
SMTP Error: Could not authenticate. Mail errorSMTP Error: Could not authenticate.
请教大神是什么原因？
是不是还需要哪些设置？还是phpmailer用得不对？
谢谢！

function sendmail($to,$subject,$msg)
{
require_once "PHPMailer/class.phpmailer.php";
include('PHPMailer/class.smtp.php');

$mail = new PHPMailer(); //创建实例$mail -> CharSet='utf-8'; //设置字符集$mail -> SetLanguage('en','include/PHPMailer/language/');  //设置语言类型和语言文件所在目录$mail -> IsSMTP(); //使用SMTP方式发送$mail -> SMTPAuth = false; //设置服务器是否需要SMTP身份验证$mail -> Host = "smtp.163.com"; //SMTP 主机地址$mail -> Port = 25; //SMTP 主机端口$mail -> From = "ajw211@163.com"; //发件人EMAIL地址$mail -> FromName = 'ajw211'; //发件人在SMTP主机中的用户名$mail -> Username = "anthony"; //发件人的姓名$mail -> Password = "**************"; //发件人在SMTP主机中的密码$mail -> Subject = $subject; //邮件主题$mail -> AltBody = 'text/html'; //设置在邮件正文不支持HTML时的备用显示$mail -> Body = $msg;//邮件内容做成$mail -> IsHTML(true);  //是否是HTML邮件$mail -> AddAddress($to,'zy10601'); //收件人的地址和姓名$mail -> AddReplyTo($to,'zy10601'); //收件人回复时回复给的地址和姓名//$mail -> AddAttachment('include/id.csv','att.csv');//附件的路径和附件名称if(!$mail->Send()){    echo "Mail error" . $mail->ErrorInfo;}else{    echo "suucceed!!";}

}
$to = $_POST['toemail'];
$subject = $_POST['title'];
$msg = $_POST['content'];
sendmail($to,$subject,$msg);