Getting Exception when sending mail using SMTP

MailMsg            = new MailMessage();
MailMsg.IsBodyHtml = true;

 
TheCredential      = new System.Net.NetworkCredential("xxxxx", "xxxx");

 
MailMsg.From       = new MailAddress("xxxxxx");
MailMsg.Priority   = MailPriority.Normal;

 
SMTPClient = new System.Net.Mail.SmtpClient("xxxxxx", 25);

 
ServicePointManager.ServerCertificateValidationCallback = delegate(object s, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors) 
{ 
    return true; 
};

 
SMTPClient.UseDefaultCredentials = false;
SMTPClient.Credentials = TheCredential;
SMTPClient.EnableSsl = false;

 
MailMsg.IsBodyHtml = true;
MailMsg.To.Add(To);
MailMsg.Subject = Subject;
string htmlBody = Body;

 
AlternateView htmlView = AlternateView.CreateAlternateViewFromString
                         (htmlBody, 
                          null, 
                          MediaTypeNames.Text.Html);
MailMsg.AlternateViews.Add(htmlView);

 
try
{
    MailMsg.BodyEncoding = System.Text.Encoding.UTF8;
    SMTPClient.Send(MailMsg);
    return "Mail Sent Successfully";
}
catch(Exception ex)
{
}