Build errors with Gradle - Exoplayer2 Unity (2019.2.15f1)

Creating an
Oculus Go app with Unity (Windows 10), I got  Gradle build errors.

Much of
them related to the following error: "package com.google.android.exoplayer2 does not exist”.

Re-installed
last version of Unity (2019.2.15f1) from scratch and nothing changed.

Advice would be appreciated.

Thanks

Michel