Why does my Android Auto app say "Phone not supported" After 2 weeks

A

AC Question

So, we just got an Opel (Or Vauxhall) Astra Sports Tourer 2016, and it supports Android Auto. 2 weeks before, we tested an Skoda Octavia 2016, that also supported Android Auto. With the Skoda, all worked fine. Now, after 2 weeks, randomly the app says "Phone not supported". I have factory reseted 2 times and reinstalled many times. How could i fix this?

Phone: Huawei Honor 7
Android version: Android 6.0