i'm having a serious problem... help me !!!

public partial class TestEmail : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void btnSendEmail_Click(object sender, EventArgs e)
    {
        MailMessage mail = new MailMessage();

        NetworkCredential cred = new NetworkCredential("example@hotel.allmyanmarbooking.com", "mydomainpassword"); //client's gmail and password

        mail.To.Add("ToUserAccount@gmail.com");
        mail.Subject = "Test Email"; //message subject

        mail.From = new MailAddress("example@hotel.allmyanmarbooking.com", "example@hotel.allmyanmarbooking.com");
        

        mail.IsBodyHtml = true;
        mail.Body = "trying to send to from domain email account"; //message body

        SmtpClient smtp = new SmtpClient();
        smtp.Host = "smtp.allmyanmarbooking.com";
        smtp.Port = 26;
        smtp.UseDefaultCredentials = false;
        smtp.EnableSsl = false;
        smtp.Credentials = cred;
        smtp.DeliveryMethod = SmtpDeliveryMethod.Network;

            smtp.Send(mail);       

        lblEmail.Text = "Send Successful..";
    }
}

No connection could be made because the target machine actively refused it 66.197.198.196:26
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it 66.197.198.196:26

Source Error:

Line 37:         smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
Line 38: 
Line 39:             smtp.Send(mail);       
Line 40: 
Line 41:         lblEmail.Text = "Send Successful..";