When vApp Network is no longer used and need to delete due to cleanup task, unable to delete it as there is no option to.
The OrgVDC Network also may show the error when trying to delete "Network [Network Name] cannot be deleted, because it is in use by the following vApp Networks: [Network Name]"
vCloud Director
Networks that are added to vApp are unable to be removed or edited if the vApp is in a Powered On State.
Power off vApp and the options to Delete and Edit will show.