I've been doing some tests and the app is starting fine in my Windows 10. I disconnected the ethernet connection and put the pc in flight mode, and I was still able to start and use the app.
Can you check if the same happens in other Windows 10 devices (if you have access to any)?
Also, can you please download the "Windows 7 and 8 Installer" from here and check if it works for you in offline? This .exe is meant for Windows 7 and 8, but it should work in Windows 10 too. Please uninstall your installed version before running this one.