I recently modeled a protein which plays a vital role in mycobacterium tuberculosis and docked the whole set of drugs which i downloaded from drugbank, none of the drugs docked

but when i subjected all those drugs to PREPARE LIGAND protocol and when i docked it again, i was able to get more than 24000 poses. could any one explain me why i was unable to get when i docked the drugs directly.

will the drug changes its conformation inside the cell rather than being stable in a single conformation.