We have created a transport rule that enforces TLS however we would like an exception for encrypted messages, so that this enforce TLS is not applied on already encrypted emails. but I am not able to find how to set this exception.
We have tried with these exceptions: Message type encrypted Message type permission controlled 'Content-Class' header contains ''XXXX'' Attachment file name 'XXXXX'
Any clue how I can make it possible to enforce TLS for all none encrypted messages?
