Look in the server task log and see if the response is even being triggered. If its not then that is why the emails are not being sent. If it is then it should contain some logging in the server task log if it has any problems sending the email.
It is not a server task but an automatic answer (not a planned task) and it is not logged in the server task.
Automatic responses (if they actually trigger) are logged in the server task log.
I have found my mistakes !
It is only for threat event (not for client or server) in automatic answers
AND you have to put VSE8.8