ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI%3DInChI%3D1S/C2O4/c3-1-5-2%284%296-1/file?format=sdf&get3d=True  -- InChI%3DInChI%3D1S/C2O4/c3-1-5-2%284%296-1 could not be loaded.