Android Auto does not show notifications

[Barrie-Wilson]

Hi, I have already been in contact with Google about this but I have had no response back about it. So ever since I started using Android Auto on my Samsung Galaxy S21 Ultra no notifications show on the cars head unit, but they show on my phone. Has anyone else had this issue and have been able to resolve it? I've pretty much tried every way possible from different USB cables, updating apps, clearing cache, re-installing the app and restarting my phone. But I have had no luck. Any help from anyone would be great. 

[kacnje]

AFAIK this is a known "Android Auto"'s problem. Why Google doesn't solve it, I don't know.
I have the same problem (Samsung Galaxy S21 FE), but it isn't related to the phone, cable or infotainment. There are many posts on different forums.
At first, I thought that this is Messenger's problem, but it looks this is not true.
Now I'm using a Carsifi (here is a review on my blog), but nothing changed. The Messenger notification don't show.