Hello Mike,
I just ran into the same issue and completed a first ride without shifting 
. However, good news in my case. Got it to work.
In the end what made it work for me was to disable Wi-fi and re-start the Elite Justo 2.
Before that I did the usual stuff:
1/ upgrade the Justo 2 to version 36 over Wi-Fi with the upgrado app
2/ upgrade the Zwift controllers through the Zwift companion app
I kept getting the pop-up that virtual shifting was not supported by the smart trainer.
Solution for me: Disable Wi-Fi (forget Wi-fi in the myEtraining app). After that re-powered the Justo and tried a Zwift ride. Success!
Of course with that you disable the automatic updates. So, it does not look like a good permament fix.
Hope it works for you.
Cheers,
Diederik