Error in Email sending

Hi all,

I have used the below code to send an email. when I am running the job getting a message as below and mail has not been received. I have checked the SMTP.

static boolean VMsendEmail()
{
SysEmailParameters parameters = SysEmailParameters::find();

System.Net.Mail.SmtpClient mailClient;
System.Net.Mail.MailMessage mailMessage;
System.Net.Mail.MailAddress mailFrom;
System.Net.Mail.MailAddress mailTo;
System.Net.Mail.MailAddressCollection mailToCollection;
System.Net.Mail.MailAddressCollection mailCCCollection;
System.Net.Mail.AttachmentCollection mailAttachementCollection;
System.Net.Mail.Attachment mailAttachment;
System.Net.NetworkCredential mailCredentials;
SysEmailTable sysemailtable;
Map mappings = new Map(Types::String, Types::String);
Enumerator en ;
System.Exception e;
List toList;
ListEnumerator le;
str em;

SMTPRelayServerName mailServer;
SMTPPortNumber mailPortNumber;
SMTPUserName mailUserName;
SMTPPassword mailPassword;

InteropPermission interopPermission;
;

try
{
interopPermission = new InteropPermission(InteropKind::ComInterop);
interopPermission.assert();

if (parameters.SMTPRelayServerName)
{
mailServer = parameters.SMTPRelayServerName;
}
else
{
mailServer = parameters.SMTPServerIPAddress;
}

mailPortNumber = parameters.SMTPPortNumber;
mailUserName = parameters.SMTPUserName;
mailPassword = SysEmailParameters::password();
mailCredentials = new System.Net.NetworkCredential(mailUserName,mailPassword);

mailClient = new System.Net.Mail.SmtpClient(mailServer, mailPortNumber);
mailFrom = new System.Net.Mail.MailAddress(parameters.SMTPUserName); //fromAddress);

toList = strSplit("sivakumarm@stablesoft.in",';');
en = toList.getEnumerator();

while (en.moveNext())
{
em = en.current();

le = toList.getEnumerator();
le.moveNext();

mailTo = new System.Net.Mail.MailAddress(strLTrim(strRTrim(le.current())));
mailMessage = new System.Net.Mail.MailMessage(mailFrom, mailTo);

mailToCollection = mailMessage.get_To();
}//msk
while(le.moveNext())
{
mailToCollection.Add(strLTrim(strRTrim(le.current())));
}

mailMessage.set_From(mailFrom);
mailMessage.set_ReplyTo(mailFrom);
mailMessage.set_Priority(System.Net.Mail.MailPriority::High);
mailMessage.set_Subject("Test Mail");
mailMessage.set_IsBodyHtml(true);
mailMessage.set_Body("Hi i am from ax");

mailClient.set_EnableSsl(true);
mailClient.set_UseDefaultCredentials(false);
mailClient.set_Credentials(mailCredentials);

mailClient.Send(mailMessage);

mailMessage.Dispose();

CodeAccessPermission::revertAssert();
info("Email has been send.");
return true;

}
catch (Exception::CLRError)
{
e = ClrInterop::getLastException();
while (e)
{
info(e.get_Message());
e = e.get_InnerException();
}
CodeAccessPermission::revertAssert();
return false;
}
}