ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI%3DInChI%3D1S/C2H8N2.H4N2/c1-4%282%293%3B1-2/h3H2%2C1-2H3%3B1-2H2/file?format=sdf&get3d=True  -- InChI%3DInChI%3D1S/C2H8N2.H4N2/c1-4%282%293%3B1-2/h3H2%2C1-2H3%3B1-2H2 could not be loaded.