ERROR opening https://cactus.nci.nih.gov/chemical/structure/C%5Bn%2B%5D1%3Dcc%3Dc%28c%3Dc1%29c2%3Dcc%3Dcc%3Dc2/file?format=sdf&get3d=True  -- C%5Bn%2B%5D1%3Dcc%3Dc%28c%3Dc1%29c2%3Dcc%3Dcc%3Dc2 could not be loaded.