We have set up our ServiceDesks to only create issues from registered customers. What we would like to do, is to inform the sender of an e-mail, that his message got rejected because he isn't registered. With that information he should be able to message our team directly and they can check if he should be eligible to send tickets to our service desk.
Currently we don't know of a way to solve this problem, and googling around there were only discussions about how to set up the email puller correctly.
So does anybody know, how to set up such an e-mail reply?
Kind regards,
Julian