This usually has a technical reason and has multiple ways to resolve.
Technically moreViz works by copying the contents of the host application and pasting them into the moreViz client for viewing in any VR environment.
That concludes that only geometry visible in the 3D viewport of the host app can be transferred into VR.
Place the camera in the Host app in a perfect way
Many applications have a “Fit all” or “Show all” function. Use it to visualize all content of the 3D scene in the VR environment of the moreViz client.
Many apps have specific best settings to apply, see the individual moreViz profile for your application.