This was my code that worked, stopped working, but now works:
System.Web.Mail.MailMessage Mail1 = new System.Web.Mail.MailMessage();
Mail1.From = "
[email protected]";
Mail1.To = txtEmail.Text;
Mail1.Subject = "Subject";
Mail1.Body = "Body";
System.Web.Mail.SmtpMail.Send(Mail1)...