ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI%3DInChI%3D1S/C6H4N2O4/c9-4-2-1-3%287-11%296%2810%295%284%298-12/h1-2%2C9-10H/file?format=sdf&get3d=True  -- InChI%3DInChI%3D1S/C6H4N2O4/c9-4-2-1-3%287-11%296%2810%295%284%298-12/h1-2%2C9-10H could not be loaded.