邮件发送不成功,该怎么处理

邮件发送不成功
大家好,帮忙看下以下代码为什么发送不成功?谢谢

  protected   void   Button1_Click(object   sender,   EventArgs   e)
        {
                string   mailfrom   =   "yanlong_521521521@163.com ";
                string   name   =   mailfrom.Substring(0,   mailfrom.IndexOf( "@ "));
                MailMessage   mes   =   new   MailMessage(mailfrom,   "yanlong_521521@163.com ",   "祝福 ",   "好好 ");
                mes.BodyEncoding   =   System.Text.Encoding.GetEncoding( "gb2312 ");
                mes.IsBodyHtml   =   true;
                SmtpClient   client   =   new   SmtpClient( "smtp.163.com ");
                client.Credentials   =   new   NetworkCredential(name,   "来自邮件密码 ");
                client.Send(mes);
        }

错误提示说:邮箱不可用。   服务器响应为:   Óû§±»Ëø¶¨
请问一下,怎么解决呢.谢谢.

[解决办法]
mailObj.Fields.Add( "http://schemas.microsoft.com/cdo/configuration/smtpauthenticate ", "1 ");
mailObj.Fields.Add( "http://schemas.microsoft.com/cdo/configuration/sendusername ", this._MailFrom);
mailObj.Fields.Add( "http://schemas.microsoft.com/cdo/configuration/sendpassword ", this._MailFromPwd);

[解决办法]
我的可以发呀,不行你加上这句 client.DeliveryMethod = SmtpDeliveryMethod.Network;


client.Credentials = new NetworkCredential(name, "来自邮件密码 ");
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.Send(mes);