ZixGateway uses the following default messages for emails that match the policy. You can define a custom message for each policy.
Default routing message for Send per Policy:
This email was delivered to its intended recipient(s) however it may have contained information that does not comply with corporate policies (security or otherwise) for transmission over the Internet, in which case it should have been encrypted.
Default routing message for Do Not Send:
The email you attempted to send may have
contained information that does not comply with corporate policies (security or
otherwise) for transmission over the Internet. Please review the subject line,
message body and attachments.