Cubase 7.5... Kontakt 5/6... 32/64bit


Recently updated Cubase 7.5 to 7.5.4, on Mac Os Mojave 10.14.6. Have also updated Kontakt 5. Now when I open Cubase and open Kontakt it is not working. Kontakt 5 is in my VST list and I can select it but when I do this it is faded out on the track arm.
I am at a loss and have someone waiting for some stems! Can anyone help?