According to this thread on Google’s forums, Android Auto simply crashes immediately after the launch. In other words, the phone is connected to the head unit, Android Auto fires up, and boom, it crashes without users even managing to tap something on the screen.
“I can try 100 times, but same thing happens. Each time the charging starts and then stops after a second,” someone explains in a discussion thread on the forums.
At first glance, the cable appears to be the one to blame, so certainly, replacing it with a new high-quality cord should do the trick. Well, that doesn’t seem to be the case this time, or at least, not according to these users.
“I tried to connect with 2 different cables (genuine Samsung), changed Default USB configuration with ‘Transferring Files’, reinstalled the app several times, and still got the same problem,” another user struggling with the same problem explains.
Judging from these posts, Samsung phones are most often affected by this problem, but others claim the same thing happens in their cars, even with a Google Pixel or Nokia models. This seems to indicate Android Auto is the one requiring a fix, though, of course, Google has remained completely tight-lipped on the whole thing for now.
No workaround is known to exist for the time being, so your best option is to just reach out to Google for additional assistance.