ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI%3DInChI%3D1S/C6H4N4/c1-2-9-6-5%288-1%293-7-4-10-6/h1-4H/file?format=sdf&get3d=True -- InChI%3DInChI%3D1S/C6H4N4/c1-2-9-6-5%288-1%293-7-4-10-6/h1-4H could not be loaded.