I submitted PDB structures via HADDOCK Server 2.4, which contain SF4, e.g.:
HETATM 2466  S1  SF4 X 412     106.593  23.084  21.145  1.00 56.77      X    S
…
HETATM 2473 FE4  SF4 X 412     107.507  21.347  22.399  1.00 62.48      X   FE
However, the server shows the following error:
The following error occurred when processing one of your PDB file: Unable to generate topology for ligand IOD. PRODRG did not create the required output.
How can i submit PDB structure with SF4 ligand.
Thanks for helping.