ERROR opening https://cactus.nci.nih.gov/chemical/structure/C1%26%2361%3BNN%26%2361%3BCN%26%2361%3BN1/file?format=sdf&get3d=True -- C1%26%2361%3BNN%26%2361%3BCN%26%2361%3BN1 could not be loaded.