Check failure response of email - asp.net

Question

How to check failure response in email send method using Asp.Net.
The Problem is i didn't get the failure exception.
Please suggest better way.
Here is my code, i'm trying to access the email failure exception...
public static bool sendMail(string strTo, string strSubject, string strName, string strbody)
{
try
{
strName = strName == "" ? "Sir/Madam" : ("Dear " + strName + ",");
StringBuilder mailbody = new StringBuilder();
SmtpClient mailClient = null;
MailMessage message = null;
mailClient = new SmtpClient();
message = new MailMessage();
mailClient.Host = ConfigurationManager.AppSettings["SMTP_MAIL_SERVER"];
mailClient.Port = int.Parse(ConfigurationManager.AppSettings["PORT"]);
//network credentials
string strMailUserName = ConfigurationManager.AppSettings["FROM_ADDR"];
string strMailPassword = ConfigurationManager.AppSettings["FROM_ADDR_PASS"];
string strWebSiteURL = ConfigurationManager.AppSettings["LinkTosite"];
mailClient.EnableSsl = true;
System.Net.NetworkCredential SMTPUserInfo = new System.Net.NetworkCredential(strMailUserName, strMailPassword);
mailClient.UseDefaultCredentials = true;
mailClient.Credentials = SMTPUserInfo;
string strFromMail = ConfigurationManager.AppSettings["FROM_ADDR"];
MailAddress fromAddress = new MailAddress(strFromMail, "TEST (Administrator)");
message.From = fromAddress;
message.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure | DeliveryNotificationOptions.OnSuccess;
//to mail address
message.To.Add(strTo);
message.Subject = "ChatOnGo : " + strSubject;
//mailbody.AppendFormat("<link href='" + strWebSiteURL + "admin/css/bestlogin.css' rel='stylesheet' type='text/css' />");
mailbody.AppendFormat("<div class='dlogin_bg'><div class='dlogin_bg_top'></div><div class='dlogin_bg_bottom'><h2>" + strName + "</h2>");
mailbody.AppendFormat(strbody);
mailbody.AppendFormat("<br/><br/><span>Regards,<br /><a href='" + strWebSiteURL + "'>ChatOnGo Admin</a></span></div></div>");
message.Body = mailbody.ToString();
message.IsBodyHtml = true;
mailClient.SendMailAsync(message);
message = null;
mailClient = null;
return true;
}
catch (SmtpFailedRecipientsException ep)
{
Console.WriteLine(ep.Message);
return false;
}
catch (Exception ep)
{
Console.WriteLine(ep.Message);
return false;
}
}

Answer 1

I assume you are using gmail to send email.
You should send the email at least once and if the email is not valid you will receive failure notification.
You can create a nightly/hourly job to check these failure emails and mark them as invalid in your database.
Below is the link to read emails programatically :
http://www.aspsnippets.com/Articles/Fetch-and-read-email-messages-with-attachments-from-GMAIL-POP3-mail-server-in-ASPNet.aspx
I hope this helps!

Answer 2

I am not sure but can you try to send mail without Async (SendMailAsync), just try to call normal send method, probably you will get exception details.