Android Auto not allowing Spotify to be used as a media playback source

[JLieblich]

I was previously using Spotify with my Pixel 3 XL with no problems. After getting another device (Pixel 3a), I found that Spotify was no longer being presented as an option for media playback in my 2019 Subaru Forester's system. I have tried all of the generic troubleshooting steps without any luck.

[socamb]

I have this same issue. Spotify was available in my moto g4 phone, not in my pixel 3a.