Is it possible to use different forcefields for protein and ligand when running MD simulation?

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GROMACS version: 2023.3
GROMACS modification: Yes/No
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I’m trying to perform MD simulation for viral protein-ligand complex. I plan to use CHARMM27 all-atom force field (CHARM22 plus CMAP for proteins) for the viral protein and then CHARMM all-atom force field for the small drug-like compound.

I encountered a fatal error (atom C1 not found in buiding block 1MET while combining tdb and rtp) when using CHARMM all-atom force field for the protein. -ter and -ignh do not work, nothing I do works. However, it ran perfectly when I used CHARMM27 all-atom force field (CHARM22 plus CMAP for proteins)

I will assign ligand topology to the small drug-like mol.

Would the result be affected or is it alright to proceed?