I have clients who have repeatedly had email problems. The latest one has many emails sent to him that are rejected. Some senders have notified him and the latest one sent the error message he received:
Unknown user:
RCPT TO generated following response:
550 Rejected by final destination
This was to an email address that was created several months ago. Any information you can provide would be appreciated. He has reached the point of frustration where he wants to look for another host.
I can’t say because we haven’t received any complaint like this so far.
I send/receive a large number of email myself, no issue here.
Could you submit a ticket with the full returned email so we can investigate and send test emails.
Returned emails could also be emails caused by someone who is mass mailing with your email address with fake headers
I created a ticket (#34927) and attached the email.
Your ticket has been replied. Kindly check it.
The mail account mentioned doen’t seems to
have any problem, neither do the mail server
has. See if the client faces the problem again
and ask him to send the mailer-daemon email
as attachment.
Also kindly ask the client if the problem has
been reported by the same sender each time
and with the same error.