So i have a kinect program which when it detects a human, it saves images of them and sends your email a notification email, the thing is that when it sends the email, it freezes and stops running, Why does it do this? Email Notification Code:

  void SendNotificationEmail()
    {
        string email = textBox1.Text;
        string message = "Someone has been detected in your house!\n Go to www.kinected.webs.com to view your photos now!!!!";
        System.Net.Mail.MailMessage emailsend = new System.Net.Mail.MailMessage();
        emailsend.To.Add(email);
        emailsend.Subject = "There is an Intruder In Your Home!";
        emailsend.From = new System.Net.Mail.MailAddress("[email protected]");
        emailsend.Body = message;
        System.Net.Mail.SmtpClient smtp = new System.Net.Mail.SmtpClient("smtp.mail.yahoo.com.");
        smtp.Send(emailsend);
    }

When its supposed to fire:

        void nui_ColorFrameReady2(object sender, ImageFrameReadyEventArgs e)
    {
        // 32-bit per pixel, RGBA image  xxx
        PlanarImage Image = e.ImageFrame.Image;
        //int deltaFrames = totalFrames - lastFrameWithMotion;
        //if (totalFrames2 <= stopFrameNumber & deltaFrames > 300)
        {
           ++totalFrames2;
            string bb1 = Convert.ToString(totalFrames2);
            // string file_name_3 = "C:\\Research\\Kinect\\Proposal\\Depth_Img" + bb1 + ".jpg"; xxx
            string file_name_4 = "C:\\temp\\Kinect1_Img" + bb1 + ".jpg";
            video.Source = BitmapSource.Create(
                Image.Width, Image.Height, 96, 96, PixelFormats.Bgr32, null, Image.Bits, Image.Width * Image.BytesPerPixel);

            BitmapSource image4 = BitmapSource.Create(
                Image.Width, Image.Height, 96, 96, PixelFormats.Bgr32, null, Image.Bits, Image.Width * Image.BytesPerPixel);

            if (PersonDetected == 1)
            {
                if (totalFrames2 % 10 == 0)
                {
                    image4.Save(file_name_4, Coding4Fun.Kinect.Wpf.ImageFormat.Jpeg);
                    SendNotificationEmail();
                    PersonDetected = 0;
                    // lastFrameWithMotion = totalFrames;
                    // topFrameNumber += 100;
                }
            }
        }

    }

Thanks for any help!