[SOLVED] answer by email to an external user by input mailbox for tickets

hello,

when we use the input mailbox by tickets, the sender's email address is automatically populated in the external reference field.
In the ticket-related mailbox configuration menu, there is a checkbox specifying that the sender can automatically be added to the ticket tracking, but it's not work ...
My question is: is it possible, without creating a user account, for the person who sent the "ticket" email to receive feedback on its status during processing? Is it possible, without creating a user, to at least create a contact with this new address so that the ticket can be tracked back to the sender?