System.Net.Mail.SmtpFailedRecipientException: Mailbox unavailable.
I have a registration page that the users register and get an email verification. We seem to be able to do that in our network; however, if external users want to register, they never got the email. I looked at the event log and it says:
Code:
System.Net.Mail.SmtpFailedRecipientException: Mailbox unavailable. The server response was: 5.7.1 Unable to relay for [email protected]
Re: System.Net.Mail.SmtpFailedRecipientException: Mailbox unavailable.
Do you know for a fact that [email protected] exists?
