no midi sound

no indication led (light) in my XP-50 - but never before I saw an indication on the XP-50 - only in cubase. Before I used to play with my M-Audio card which was connected in the same routing as now and it was working perfectly.
I can play VST instrument such as Halion from my XP-50 which is included in the Cubase AI-7 but I can’t use my XP-50 separately and to get the sounds from my XP-50.