FirebaseStorage returning unknown error when requesting image

I just noticed that the httpresult is zero. This suggests the request to get the download url was never made. One way this can happen is if play services isn't updated on your phone. You will know this is the error because adb logcat will show an error with something to the effect of "Storage network layer could not be loaded".

To fix this, update play services on your phone. There are a few ways of doing this. I find the easiest is to install the app "play services info" to see play services in the play store, and then hit update if its available.

Update Google Play Services on your device, not in your gradle script (though do that, too).

After banging my head against the wall for about an hour due to only skimming benjamin-wulfe's answer as well as others on the internet, I came back and read it carefully. Hope this will help others avoid my mistake!