RejectedRecipient Event

public event EventHandler<TEventArgs> RejectedRecipient

Public Event RejectedRecipient EventHandler(Of TEventArgs)

public:
 event EventHandler<TEventArgs>^ RejectedRecipient

Show how to handle the RejectedRecipient event.

using System;
using System.Windows.Forms;
using ComponentPro.Net;
using ComponentPro.Net.Mail;

...

public void HandleRejectedRecipientEvent()
{
    const string serverName = "myserver";
    const string user = "name@domain.com";
    const string password = "mytestpassword";
    const int port = 465;
    const SslSecurityMode securityMode = SslSecurityMode.Implicit;

    // Create a new instance. 
    Smtp client = new Smtp();

    client.RejectedRecipient += client_RejectedRecipient;

    try 
    {
        MailMessage mmMessage = new MailMessage();
        mmMessage.From.Add("from@thedomain.com");
        mmMessage.To.Add("name@domain.com");
        mmMessage.To.Add("someone@domain.com");
        mmMessage.CC.Add("someone2@domain.com");
        mmMessage.Bcc.Add("someone3@domain.com");
        mmMessage.Subject = "Test Subject";
        mmMessage.BodyText = "Test Content";

        Console.WriteLine("Connecting SMTP server: {0}:{1}...", serverName, port);
        // Connect to the server. 
        client.Connect(serverName, port, securityMode);

        // Login to the server. 
        Console.WriteLine("Logging in as {0}...", user);
        client.Authenticate(user, password);

        Console.WriteLine("Sending mail message...");
        client.Send(mmMessage);
        Console.WriteLine("Message sent...");

        // Disconnect. 
        Console.WriteLine("Disconnecting...");
        client.Disconnect();
    }
    catch (SmtpException smtpExc)
    {
        MessageBox.Show(string.Format("An SMTP error occurred: {0}, ErrorStatus: {1}", smtpExc.Message, smtpExc.Status));
    }
    catch (Exception exc)
    {
        MessageBox.Show(string.Format("An error occurred: {0}", exc.Message));
    }

    // ... 
 
    // Disconnect. 
    client.Disconnect();
}

void client_RejectedRecipient(object sender, SmtpRejectedRecipientEventArgs e)
{
    Console.WriteLine("Recipient rejected: " + e.Recipient);
}

Imports ComponentPro.Net
Imports ComponentPro.Net.Mail

...

Public Sub HandleRejectedRecipientEvent()
    Const serverName As String = "myserver" 
    Const user As String = "name@domain.com" 
    Const password As String = "mytestpassword" 
    Const port As Integer = 465
    Const securityMode As SslSecurityMode = SslSecurityMode.Implicit

    ' Create a new instance. 
    Dim client As New Smtp()

    AddHandler client.RejectedRecipient, AddressOf client_RejectedRecipient

    Try 
        Dim mmMessage As New MailMessage()
        mmMessage.From.Add("from@thedomain.com")
        mmMessage.To.Add("name@domain.com")
        mmMessage.To.Add("someone@domain.com")
        mmMessage.CC.Add("someone2@domain.com")
        mmMessage.Bcc.Add("someone3@domain.com")
        mmMessage.Subject = "Test Subject" 
        mmMessage.BodyText = "Test Content" 
 
        Console.WriteLine("Connecting SMTP server: {0}:{1}...", serverName, port)
        ' Connect to the server. 
        client.Connect(serverName, port, securityMode)

        ' Login to the server. 
        Console.WriteLine("Logging in as {0}...", user)
        client.Authenticate(user, password)

        Console.WriteLine("Sending mail message...")
        client.Send(mmMessage)
        Console.WriteLine("Message sent...")

        ' Disconnect. 
        Console.WriteLine("Disconnecting...")
        client.Disconnect()
    Catch smtpExc As SmtpException
        MessageBox.Show(String.Format("An SMTP error occurred: {0}, ErrorStatus: {1}", smtpExc.Message, smtpExc.Status))
    Catch exc As Exception
        MessageBox.Show(String.Format("An error occurred: {0}", exc.Message))
    End Try 
 
    ' ... 
 
    ' Disconnect. 
    client.Disconnect()
End Sub 
 
Private Sub client_RejectedRecipient(ByVal sender As Object, ByVal e As SmtpRejectedRecipientEventArgs)
    Console.WriteLine("Recipient rejected: " & e.Recipient)
End Sub

Reference