It almost seems like I'm the only one with the USB connection working. 
For me it works
- on 2 different notebooks,
- on 3 different PCs
- with Win7 / Win10
- with 15 different test devices (Android 4.x, 5.x, 7, 8.x, 9, 10, 11)
and that for many years; actually since my first days with App Inventor.
USB - video
So where could the problem be? 
