Exactly the same problem on my iPhone11pro, sometimes works right away, sometimes need to press different buttons, disconnect - connect few times.... not sure what is going on...Apple car play works intermittently and I can’t find any logical patterns for when it will and won’t work. I can stop the car for gas and when I start back up it won’t connect. It’s maddening! We never have problems with our Ford. I appreciate it’s apple software/interface, but GMC purchased it and marketed it’s availability to their customers. Therefore it’s their accountability (to their customers) to make it work on their vehicles.