Deployed app on Oculus go shows but not starts

Hello,
by following the official Oculus Go related tutorial to package my project (UE4.21.1) I was eventually able to deploy it on the Go.
Now I can the app shows up under the “unknown sources” tab inside the Oculus Go, but when I click on it, after a few seconds of black screen, nothing happens. Can someone help me, please?

Hello ,

Have you set your “Game Default Map” in Edit → Project Settings → Maps & Modes?

This is the map that will open for packaged projects.