static void send(string subject, User to) { try { MailBuilder builder = new MailBuilder(); builder.Html = @"Html with an image: <img src=""cid:lena"" />"; builder.Subject = subject; MimeData visual = builder.AddVisual(HostingEnvironment.MapPath("~/Images/logo_2.png")); visual.ContentId = "lena"; MimeData attachment = builder.AddAttachment(@"C:\Users\User\Desktop\Attachment.txt"); attachment.FileName = "document.doc"; builder.From.Add(new MailBox("*****@*****.**")); builder.To.Add(new MailBox(to.Email)); //builder.To.Add(new MailBox("*****@*****.**")); IMail email = builder.Create(); using (Smtp smtp = new Smtp()) { smtp.Connect(_server); // or ConnectSSL for SSL smtp.UseBestLogin(_user, _password); smtp.SendMessage(email); smtp.Close(); } } catch (Exception e) { Console.WriteLine(e.Message); } }