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MimeKit

SmtpProtocolException Class

An SMTP protocol exception.
Inheritance Hierarchy

Namespace:  MailKit.Net.Smtp
Assembly:  MailKit (in MailKit.dll) Version: 2.3.0
Syntax
C#
[SerializableAttribute]
public class SmtpProtocolException : ProtocolException

The SmtpProtocolException type exposes the following members.

Constructors
  NameDescription
Public methodSmtpProtocolException
Initializes a new instance of the SmtpProtocolException class.
Public methodSmtpProtocolException(String)
Initializes a new instance of the SmtpProtocolException class.
Protected methodSmtpProtocolException(SerializationInfo, StreamingContext)
Initializes a new instance of the SmtpProtocolException class.
Public methodSmtpProtocolException(String, Exception)
Initializes a new instance of the SmtpProtocolException class.
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Properties
  NameDescription
Public propertyData
Gets a collection of key/value pairs that provide additional user-defined information about the exception.
(Inherited from Exception.)
Public propertyHelpLink
Gets or sets a link to the help file associated with this exception.
(Inherited from Exception.)
Public propertyHResult
Gets or sets HRESULT, a coded numerical value that is assigned to a specific exception.
(Inherited from Exception.)
Public propertyInnerException
Gets the Exception instance that caused the current exception.
(Inherited from Exception.)
Public propertyMessage
Gets a message that describes the current exception.
(Inherited from Exception.)
Public propertySource
Gets or sets the name of the application or the object that causes the error.
(Inherited from Exception.)
Public propertyStackTrace
Gets a string representation of the immediate frames on the call stack.
(Inherited from Exception.)
Public propertyTargetSite
Gets the method that throws the current exception.
(Inherited from Exception.)
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Methods
  NameDescription
Public methodEquals
Determines whether the specified object is equal to the current object.
(Inherited from Object.)
Protected methodFinalize
Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.
(Inherited from Object.)
Public methodGetBaseException
When overridden in a derived class, returns the Exception that is the root cause of one or more subsequent exceptions.
(Inherited from Exception.)
Public methodGetHashCode
Serves as the default hash function.
(Inherited from Object.)
Public methodGetObjectData
When overridden in a derived class, sets the SerializationInfo with information about the exception.
(Inherited from Exception.)
Public methodGetType
Gets the runtime type of the current instance.
(Inherited from Exception.)
Protected methodMemberwiseClone
Creates a shallow copy of the current Object.
(Inherited from Object.)
Public methodToString
Creates and returns a string representation of the current exception.
(Inherited from Exception.)
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Events
  NameDescription
Protected eventSerializeObjectState
Occurs when an exception is serialized to create an exception state object that contains serialized data about the exception.
(Inherited from Exception.)
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Remarks
The exception that is thrown when there is an error communicating with an SMTP server. An SmtpProtocolException is typically fatal and requires the SmtpClient to be reconnected.
Examples
C#
public static void SendMessage (MimeMessage message)
{
    using (var client = new SmtpClient ()) {
        try {
            client.Connect ("smtp.gmail.com", 465, SecureSocketOptions.SslOnConnect);
        } catch (SmtpCommandException ex) {
            Console.WriteLine ("Error trying to connect: {0}", ex.Message);
            Console.WriteLine ("\tStatusCode: {0}", ex.StatusCode);
            return;
        } catch (SmtpProtocolException ex) {
            Console.WriteLine ("Protocol error while trying to connect: {0}", ex.Message);
            return;
        }

        // Note: Not all SMTP servers support authentication, but GMail does.
        if (client.Capabilities.HasFlag (SmtpCapabilities.Authentication)) {
            try {
                client.Authenticate ("username", "password");
            } catch (AuthenticationException ex) {
                Console.WriteLine ("Invalid user name or password.");
                return;
            } catch (SmtpCommandException ex) {
                Console.WriteLine ("Error trying to authenticate: {0}", ex.Message);
                Console.WriteLine ("\tStatusCode: {0}", ex.StatusCode);
                return;
            } catch (SmtpProtocolException ex) {
                Console.WriteLine ("Protocol error while trying to authenticate: {0}", ex.Message);
                return;
            }
        }

        try {
            client.Send (message);
        } catch (SmtpCommandException ex) {
            Console.WriteLine ("Error sending message: {0}", ex.Message);
            Console.WriteLine ("\tStatusCode: {0}", ex.StatusCode);

            switch (ex.ErrorCode) {
            case SmtpErrorCode.RecipientNotAccepted:
                Console.WriteLine ("\tRecipient not accepted: {0}", ex.Mailbox);
                break;
            case SmtpErrorCode.SenderNotAccepted:
                Console.WriteLine ("\tSender not accepted: {0}", ex.Mailbox);
                break;
            case SmtpErrorCode.MessageNotAccepted:
                Console.WriteLine ("\tMessage not accepted.");
                break;
            }
        } catch (SmtpProtocolException ex) {
            Console.WriteLine ("Protocol error while sending message: {0}", ex.Message);
        }

        client.Disconnect (true);
    }
}
See Also