Cannot load .babylon file in Sandbox

When I try to load this file into the Babylon Sandbox at, I get this error.

Unable to load from file:model.babylon: loadAssets of unknown Lights: Name: SconceLeft Light, type: Point Name: SconceRight.SconceLeft Light, type: Point Name: Central Light, type: Point Name: Back Light, type: Point Materials: Name: backwall Name: wallMaterial (34.0 KB)

The model loads fine (with the exception of the textures not loading - which is understandable) from a web page using

    const scene = await BABYLON.SceneLoader.LoadAsync("/", "model.babylon", engine, 

I think it does not work in the sandbox because some textures are not found: this is considered an error and the file is not loaded. Try adding the missing textures and see if that helps.