ImageBasedLighting: Failed to find EnvironmentResource with name in bundle

Hello. I am trying to load my own Image Based Lighting file in a visionOS RealityView. I used the code you get when creating a new project from scratch and selecting the immersive space to full when creating the project. With the sample file Apple provides, it works. But when I put my image in PNG, HEIC or EXR format in the same location the example file was in, it doesn't load and the error states:

Failed to find resource with name "SkyboxUpscaled2" in bundle

In this image you can see the file "ImageBasedLight", which is the one that comes with the project and the file "SkyboxUpscaled2" which is my own in the .exr format.

if let immersiveContentEntity = try? await Entity(named: "Immersive", in: realityKitContentBundle) {
                content.add(immersiveContentEntity)

                do{
                    let resource = try await EnvironmentResource(named: "SkyboxUpscaled2")
                    let iblComponent = ImageBasedLightComponent(source: .single(resource), intensityExponent: 0.25)
                    immersiveContentEntity.components.set(iblComponent)
                    immersiveContentEntity.components.set(ImageBasedLightReceiverComponent(imageBasedLight: immersiveContentEntity))
                }catch{
                    print(error.localizedDescription)
                }

Does anyone have an idea why the file is not found? Thanks in advance!