ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/C2H4N2O2/c3-1(5)2(4)6/h(H2,3,5)(H2,4,6)/file?format=sdf&get3d=True -- InChI=1S/C2H4N2O2/c3-1(5)2(4)6/h(H2,3,5)(H2,4,6) could not be loaded.