My installation is similar. Unlocking the app using Windows Hello at the beginning of a Windows session works fine, but after locking and unlocking the screen, or after many hours, I am unable to make the Windows Hello authentication run. This appears but nothing for me to click to start Windows Hello!
You need to add a button that starts a Windows Hello login session, or else offer us an alternative login method on this screen.
Even clicking this "Open Enpass" in the system notification icon makes no difference. The app window above appears when I click this, but again, there's no Windows Hello interaction:
Version I'm running:
The only way I can login is to Quit the app in the system notification tray and start again. It's very frustrating!