Hi,
- Make sure you BUILD your project (botton top toolbar).
- In project settings, under rendering, enable MobileHDR because of this bug: Unreal Engine Issues and Bug Tracker (UE-90099)
- You downloaded a project from “somewhere”, well ask them about that. We don’t use that project so we cannot know what it does. Try instead the default HandheldAR template from UE4 and examine what is different.
Good luck