Hi can you unfold an extruded shape other than rounds ? trying to unfold a shape that is elliptical

trying to unfold a part that is not extruded from a round shape it is elliptical.

I don't have a problem unfolding regular  round shapes.

Shape is extruded and then a cut made to select an edge to create a sheet metal part.

error indicates "cannot use this type of edge"

Thanks in advance

SolidworksGeneral