unity, AR app doesn't install on Android phone

I have build a vera simple AR scene, just for trying out the workflow...and build an android app. I can create the .apk file, but my phone wouldn't install it. It just gives me "App not installed". When building the app in Unity though, I get this warning:

Unity.InteractiveTutorials.BuildStartedCriterion must be instantiated using the ScriptableObject.CreateInstance method instead of new BuildStartedCriterion. UnityEngine.ScriptableObject:.ctor()

I am new to all of this, so I have no idea what to do. Any ideas? Thank you in advance!