An email message was sent to a particular domain destination. But, it bounced back and Unknown Address Error 550 error message appeared while tracking. How can we resolve it?
The error refers that the server of the recipient is not able to have a DNS look up on the connecting host name. The hostname would be the name of IP interface for which the delivery is being performed on ESA. If the IP names do not match, then the emails will bounce back bearing the same message. If the issue is not resolved, Public DNS should be able to resolve the IP interface FQDN that you have been using.
