电子邮件发送失败，但有所有例外

Question

请查看以下代码

Email.h

    #pragma once
    #include <string>

    using namespace System::Net;
    using namespace System::Net::Mail;
    using namespace System::Net::Mime;

    using namespace std;


    ref class Email
    {
    public:
        Email();

        //Sets the location of the attachment
        void setAttachment(System::String ^attachmentLocation);

        //Set the the from address of the email
        void setFromAddress(System::String ^fromAddress);

        //Set the reception's address of the email
        void setToAddress(System::String ^toAddress);

        //Set the subject pf the email
        void setSubject(System::String ^subject);

        //Set the Message of the email
        void setMessage(System::String ^emailMessage);

        //Set the SMTP client
        void setSMTPClient(System::String ^smtpClient);

        //Send the email
        void sendEmail();

    private:
        MailMessage ^mail;
        Attachment ^attachment;
        SmtpClient ^client;
    };

Email.cpp

#include "StdAfx.h"
#include "Email.h"


Email::Email()
{
    mail = gcnew MailMessage();

}

void Email::setAttachment(System::String ^attachmentLocation)
{
    attachment = gcnew Attachment(attachmentLocation);

    ContentDisposition ^disposition = attachment->ContentDisposition;
    disposition->CreationDate = System::IO::File::GetCreationTime(attachmentLocation);
    disposition->ModificationDate = System::IO::File::GetLastWriteTime(attachmentLocation);
    disposition->ReadDate = System::IO::File::GetLastAccessTime(attachmentLocation);
}

void Email::setFromAddress(System::String ^fromAddress)
{
    mail->From = gcnew MailAddress(fromAddress);
}

void Email::setMessage(System::String ^emailMessage)
{
    mail->Body = emailMessage;
}

void Email::setSMTPClient(System::String ^smtpClient)
{
    client = gcnew SmtpClient(smtpClient);
}

void Email::setSubject(System::String ^subject)
{
    mail->Subject = subject;
}

void Email::setToAddress(System::String ^toAddress)
{
    mail->To->Add(toAddress);
}

void Email::sendEmail()
{
    try
    {
        client->Send(mail);
    }
    catch(System::Exception ^e)
    {
        System::Windows::Forms::MessageBox::Show(e->ToString());
    }

}

这就是我在另一个类

中调用此类的方法

Email ^email = gcnew Email();
                     email->setToAddress("sss@yahoo.com");
                     email->setSubject("Intruder Detected");
                     email->setSMTPClient("localhost");
                     email->setMessage("sending mail. Image is attached");
                     email->setFromAddress("justsomemail@lol.com");
                     email->setAttachment("D:/OpenCV Final Year/Images/intruder.bmp");
                     email->sendEmail();

请注意，此处的From地址是非现有/非真实地址。在实际代码中也是如此。 To地址是真实的，并在此修改，因为我无法发布原始地址。

当我运行此代码时，我收到以下错误。

这是我第一次尝试使用C ++ / CLI（C ++和C＃）发送电子邮件。我记得我在Java Mail中使用localhost作为我的Java应用程序，所以我真的无法在这里找到真正的错误。