Thanks for the information. I found file "C:\Program Files (x86)\Stardock\Groupy\SasSteam.ini", so I renamed it by adding ".bak" to the end of the file name. Launched the Groupy Settings app, About, Check for Update... It said I was up to date. All I did previously when I got the initial error message "Failed to Authenticate Groupy with Steam...", I cancelled from that screen. It appears it installed/updated anyway once I cancelled the error message pop-up. Posting this detail in case it helps someone else.
Thanks,
-k-