Black Background on Camera

Hi guys, i’m still new at AR and LWRP (I’m using both),
I’m having a trouble with the camera, it only show black background with my gameobject.
Can someone help me what’s wrong?

Version:
Unity: 2019.1.8f1
LWRP: 5.7.2
ARFoundation: 2.2.0
ARCore: 2.1.0