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