请教一个关于邮件发送的问题

Question

代码如下用的是cdoConfiguration conf = new ConfigurationClass();
  conf.Fields[CdoConfiguration.cdoSendUsingMethod].Value = CdoSendUsing.cdoSendUsingPort;
            conf.Fields[CdoConfiguration.cdoSMTPServer].Value="smtp.tom.com";
conf.Fields[CdoConfiguration.cdoSMTPAccountName].Value = "zhengrongw";
            conf.Fields[CdoConfiguration.cdoSendUserReplyEmailAddress].Value="[email protected]";
    conf.Fields[CdoConfiguration.cdoSendEmailAddress].Value = "[email protected]";
            conf.Fields[CdoConfiguration.cdoSMTPAuthenticate].Value=CdoProtocolsAuthentication.cdoBasic;
            conf.Fields[CdoConfiguration.cdoSendUserName].Value="zhengrongw";//帐号
conf.Fields[CdoConfiguration.cdoSendPassword].Value="XXXXXXX";//密码
            
conf.Fields.Update(); MessageClass msg = new MessageClass();
msg.Configuration = conf;

msg.To = MailStr;
msg.Subject = "西南交通大学远程作业提交系统";
msg.TextBody = Passwd;
msg.From="[email protected]"; msg.Send();
我的帐号和密码登陆邮箱是对的
但是运行的时候显示The transport failed to connect to the server.