Try this
public string SendEmailTest(String EmailMessage, String FromMail, String MailPassword, String MailServer, String To, String CC, String BCC, String DisplayName, String Subject, String Attachment)
{
try
{
SmtpClient smtpClient = new SmtpClient();
MailMessage message = new MailMessage();
MailAddress fromAddress;
fromAddress = new MailAddress(FromMail);
smtpClient.Host = MailServer;
smtpClient.Port = 25;
System.Net.NetworkCredential SMTPUserInfo = new System.Net.NetworkCredential(FromMail, MailPassword);
smtpClient.UseDefaultCredentials = false;
smtpClient.Credentials = SMTPUserInfo;
message.From = fromAddress;
message.To.Add(new MailAddress(To, DisplayName));
if (CC != "")
message.CC.Add(new MailAddress(CC, DisplayName));
if (BCC != "")
message.Bcc.Add(new MailAddress(BCC, DisplayName));
message.Subject = Subject;
message.IsBodyHtml = true;
message.Body = EmailMessage;
if (Attachment != "")
message.Attachments.Add(new Attachment(Attachment));
message.Priority = MailPriority.High;
smtpClient.Send(message);
return "SendEmail";
}
catch (Exception ex)
{
return "Email :" + ex;
}
}