Been awhile, but I'll answer my own question.....in case someone else has same issue.
To fix non-working volume control on the laptop app, I simply get out of the app, and then open it again. It seems when it's been open for awhile, sometimes the volume control gets "sticky".
Still enjoying this thing. Liked it so much in the main rig I bought a PowerNode 2i for the 2nd system. Paired with my Wharfedale Denton (80th Anniversary) speakers produces wonderful all day background streaming. Great synergy in a simple streamlined package!

I had hesitation because of the built-in digital amp...thought it would be dry and unmusical. Quite the opposite, with these speakers the output is rich, full, warm and engaging.
PS: If you prize organic musicality these Dentons are a screaming deal when Music Direct offers them at $400 shipped. Sure they are a touch rolled on top and not the last word in transparency, but with this very reasonable $$ rig I find myself listening to music instead of sounds. Absolutely zero fatigue after 12 straight hours. Engaging performance beyond admission price.