@PeeKay47 it could be a number of factors. Have you tried simply uninstalling and reinstalling? This will fix the majority of issues with Fitbit's Windows app. It's not been updated in forever but it does function perfectly fine, I'm using it right now and it runs on all versions of Windows. If you have Fitbit connect (some old-school sync app) it will interfere and needs to be uninstalled. Make sure your dongle is plugged in when starting it up too.
Best Answer@PeeKay47 A piece of advice. Microsoft ended all support for Windows 7 in Jan 2020. This mean there a no more security updates. This can leave your system vulnerable.
Laurie | Maryland
Sense 2, Luxe, Aria 2 | iOS | Mac OS
Take a look at the Fitbit help site for further assistance and information.