ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI%3DInChI%3D1S/C2H4N4O4/c3-1%284%292%285%287%298%296%289%2910/h3-4H2/file?format=sdf&get3d=True  -- InChI%3DInChI%3D1S/C2H4N4O4/c3-1%284%292%285%287%298%296%289%2910/h3-4H2 could not be loaded.