AmorphousCellConstruct failed because the constituent molecules contain atoms with unknown forcefield atom types

Dear All
I have a molecule contains N, P, S, Cl, C, H,and O, I would like to build an Amorphous cell for this molecule. I used "Amorphous cell/Construction", and used "COMPASS" as forcefield. However, the job failed with the error "AmorphousCellConstruct failed because the constituent molecules contain atoms with unknown forcefield atom types".
Should I assign the forcefield for all abve atoms manually? If yes, how should I do?

Thank you for any suggestions and ideals.

Kind regards
Feng