The email could not be delivered because a temporary error occurred during the DNS MX query of the target domain (RCPT TO domain).
The prerequisite for accepting an email is that the DNS information for the MX server of the target domain is available.
Your email system should automatically attempt to deliver the email again at a later time using error code 4xx. It is possible that the problem will no longer occur at this time.
We therefore ask for your patience.
See also: General information on our error messages.