All emails sent from a website form must use SMTP Authentication, otherwise you will receive a "No such user here" error described in the article: https://support.aspnix.com/KB/a7/error-550-no-such-user-here.aspx

These is the sample code you can use for your email forms on websites:


ASP (with Persits)

 Set Mail = Server.CreateObject("Persits.MailSender")
 Mail.Username = "name@mydomain.com" 
 Mail.Password = "mypassword"
 Mail.Host = "mail.mydomain.com"
 Mail.From = "name@mydomain.com"
 Mail.FromName = "Questionarios Online"
 Mail.AddAddress "recipient_address", "recipient_name"
 Mail.Subject = "My Subject"
 Mail.Body = "BodyText"
 Mail.Send

ASP .Net 1.1

using System.Web.Mail;

SmtpMail.SmtpServer =  "mail.mydomain.com";
mailMsg = new MailMessage();
mailMsg.Fields["http://schemas.microsoft.com/cdo/configuration/smtpauthenticate"] = 1;
mailMsg.Fields["http://schemas.microsoft.com/cdo/configuration/sendusername"] = "name@mydomain.com";
mailMsg.Fields["http://schemas.microsoft.com/cdo/configuration/sendpassword"] = "mypassword";
mailMsg.From = "name@mydomain.com";
mailMsg.To = "recipient_address";
mailMsg.Subject = "My Subject";
mailMsg.Body = "Body text here";
SmtpMail.Send(mailMsg);

ASP .Net 2.0

In web.config file:

 <system.net>
  <mailSettings>
   <smtp from="name@mydomain.com">
    <network host="mail.mydomain.com" userName="name@mydomain.com" password="mypassword"/>
   </smtp>
  </mailSettings>
 </system.net>