When I am trying to author embed component in the "embeddable" tab I don't see any options available. according to documentation. YouTube has to show up by default
So I debugged a bit in the dialog it's trying to get options form "core/wcm/components/embed/v1/datasources/allowedembeddables" , "core/wcm/components/embed/v1/datasources/allowedembeddables" which is registered as a servlet.
In servlets i see the current source is expecting a contentpolicy. or else empty list