Unfortunately the problem is here again!
As I saw that NotePerformer was not active I cleared the audio cache button as suggested by Paul here
and restarted Dorico 3.5 and again it stays with the Audio Engine Waiting for connection 
Unfortunately the problem is here again!
As I saw that NotePerformer was not active I cleared the audio cache button as suggested by Paul here
and restarted Dorico 3.5 and again it stays with the Audio Engine Waiting for connection