ERROR opening https://cactus.nci.nih.gov/chemical/structure/InChI=1S/C4H6O4/c5-2-3(6)1-4(7)8/h2-3,6H,1H2,(H,7,8)/p-1/t3-/m1/s1/file?format=sdf&get3d=True  -- InChI=1S/C4H6O4/c5-2-3(6)1-4(7)8/h2-3,6H,1H2,(H,7,8)/p-1/t3-/m1/s1 could not be loaded.