I am receiving following error while sending email in our test domain. Mailbox unavailable. The server response was: 5.7.1 Unable to relay trace at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, Boolean allowUnicode, SmtpFailedRecipientException& exception) at System.Net.Mail.SmtpClient.Send(MailMessage message) I found similar thread, which is asking me to authenticate. "The email servers at Winhost are separate from the web servers. Also, try authenticating with the postmaster account." Can some one tell me how to do this authentication in Winhost portal. http://forum.Winhost.com/threads/mailbox-unavailable-not-permitted-to-relay.9686/
