ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI%3DInChI%3D1S/C4H8N2O2/c1-3%285-7%294%282%296-8/h7-8H%2C1-2H3/file?format=sdf&get3d=True  -- InChI%3DInChI%3D1S/C4H8N2O2/c1-3%285-7%294%282%296-8/h7-8H%2C1-2H3 could not be loaded.