For every message Admin wrote in back office the notification email is sent both to Customer and to Admin. I want this email is sent to the Customer only.
And, when a Customer wrote a message the notification email must be send to Admin only.
I just realised that following your instruction the email notification for a message wrote by a Customer is sent to “admin email address” set in Settings->General (i.e. firstname.lastname@example.org) but it is not what I want, sorry, I didn’t make myself clear. I need to send these email to other email addresses (i.e. email@example.com,firstname.lastname@example.org).