Error while running writing the topology

GROMACS version: 2023.1
GROMACS modification: Yes/No
Here post your question

I have one protein and ligand for simulation. am using charmm forcefield. when i run the command for topolgy generation:

gmx pdb2gmx -f complex_aca.pdb -o protein_aca.gro -ter

it showed the following error:
Fatal error:
The residues in the chain PCA1–LEU496 do not have a consistent type. The
first residue has type ‘Other’, while residue TYR2 is of type ‘Protein’.
Either there is a mistake in your chain, or it includes nonstandard residue
names that have not yet been added to the residuetypes.dat file in the GROMACS
library directory. If there are other molecules such as ligands, they should
not have the same chain ID as the adjacent protein chain since it’s a separate

someone please help me to solve this issue.

thank you in advance.