2019 VW JETTA-APPLE CARPLAY
I was without this feature for a week and thought I tried everything to get it to work again. It was NOT the USB cord like multiple forums said. It was NOT the iOS system I am using.
It's a RESET that happens in the car, NOT your phone. Without your phone plugged in, locate "APP Connect" on your car's display menu. Reset to Factory Settings. BOOM!! Plug your phone back in and the rest should look familiar.
iPhone 7 Plus