Hi,
With my new Kontrol S, I had two vouchers. But, impossible to use the "NI Kontakt instrument" one ! always a message saying it does not work with the selected product.
SOLUTION : first be signed out, then make your selection. You'll be asked to log in after having entered your voucher code… so all will go fine !
As usual, your product will then be available for downloading by NATIVE ACCESS app.