Why won't my Moto g Plus phone work with Android Auto

[AC Question]

Why won't my Moto G4 plus phone work with Android Auto?

 

[B. Diddy]

I think this might get a better answer in the Android Auto forum, so I moved it there.

 

[Jorakal]

Need details of the phone, version of Android, exactly what happens when you try to use Android auto, in what car, etc