ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI%3DInChI%3D1S/C4H4N2O2/c7-3-1-2-5-4%288%296-3/h1-2H%2C%28H2%2C5%2C6%29/file?format=sdf&get3d=True -- InChI%3DInChI%3D1S/C4H4N2O2/c7-3-1-2-5-4%288%296-3/h1-2H%2C%28H2%2C5%2C6%29 could not be loaded.