Has anyone successfully run Groove Agent 4 patterns in Notion 6?

As a Notion VST plug-in, Groove Agent will not play patterns from Groove Agent pad, keyboard or Notion score. When playing from a score, GA tempo is correct, track indicators increment, pad clock rotates, midi notes received but no audio output activity. Individual instruments play ok. Running Notion 6.3.454 64 bit on Windows 10 with Groove Agent 4.

What is the magic incantation to make it work? I’ve tried everything without success.