SmtpFailedRecipientsException Class

Note: This class is new in the .NET Framework version 2.0.

This class supports the .NET Framework infrastructure and is not intended to be used directly from your code.

The exception that is thrown when e-mail is sent using an SmtpClient and cannot be delivered to all recipients.

Namespace: System.Net.Mail
Assembly: System (in system.dll)

public class SmtpFailedRecipientsException : SmtpFailedRecipientException, ISerializable
/** @attribute SerializableAttribute() */ 
public class SmtpFailedRecipientsException extends SmtpFailedRecipientException implements ISerializable
public class SmtpFailedRecipientsException extends SmtpFailedRecipientException implements ISerializable

The InnerExceptions property contains the exceptions received while attempting to send e-mail. The e-mail might have been successfully delivered to some of the recipients.

The following code example resends an e-mail message that was not delivered because a mailbox was busy or unavailable.

public static void RetryIfBusy(string server)
    MailAddress from = new MailAddress("");
    MailAddress to = new MailAddress("");
    MailMessage message = new MailMessage(from, to);
    // message.Subject = "Using the SmtpClient class.";
    message.Subject = "Using the SmtpClient class.";
    message.Body = @"Using this feature, you can send an e-mail message from an application very easily.";
    // Add a carbon copy recipient.
    MailAddress copy = new MailAddress("");
    SmtpClient client = new SmtpClient(server);
    // Include credentials if the server requires them.
    client.Credentials = (ICredentialsByHost)CredentialCache.DefaultNetworkCredentials;
    Console.WriteLine("Sending an e-mail message to {0} using the SMTP host {1}.",
         to.Address, client.Host);
    catch (SmtpFailedRecipientsException ex)
        for (int i = 0; i < ex.InnerExceptions.Length; i++)
            SmtpStatusCode status = ex.InnerExceptions[i].StatusCode;
            if (status == SmtpStatusCode.MailboxBusy ||
                status == SmtpStatusCode.MailboxUnavailable)
                Console.WriteLine("Delivery failed - retrying in 5 seconds.");
                Console.WriteLine("Failed to deliver message to {0}", ex.FailedRecipient[i]);


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0

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