ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/C6H4N2O/c7-4-6-2-1-3-8(9)5-6/h1-3,5H/file?format=sdf&get3d=True  -- InChI=1S/C6H4N2O/c7-4-6-2-1-3-8(9)5-6/h1-3,5H could not be loaded.