Why the clipping editor is empty?
The logged in user don't have the permissions to edit the asset.
The file "Dynamic image cache master" is missing on the asset. In addition to the thumbnail and preview, the clipping editor also needs a specially generated storage item, the DIC master.
The trait "transformation" is missing in the declaration of the metadata application. This can be done via the widget's configuration of one of the widgets of type csMetadataWidget, which are available on the asset page. Refer the below image.
Adding the trait 'transformation' in the configuration.