Evelin Jadán The error "PDBQT parsing error: Unknown or inappropriate tag found in rigid receptor" in AutoDock Vina is often caused by unsupported tags (e.g., CONECT) in the receptor .pdbqt file. To fix this, open the gwk.pdbqt file in a text editor, remove any CONECT lines, and save it. Ensure the receptor is properly formatted as PDBQT, not just PDB or PDBQ, by regenerating it in AutoDockTools with hydrogens and Gasteiger charges. Additionally, verify that both receptor and ligand files are correctly formatted and compatible with AutoDock Vina. Alternatively, you can use PyRex software, which is easier to use and supports multi-ligand docking.