Cannot download or manually import libraries.

[totesNotRosalyn]

It gives an "Unknown error" when downloading, and it tells me I have the wrong APK, when it is the version specified by the app. (01.03.0312)

[metalmeric]

I was having the same error. What worked for me was to download the apk directly from https://play.google.com/store/apps/details?id=com.motorola.faceunlock using the website https://apps.evozi.com/apk-downloader/
Then it worked right away and I can unlock it just fine.