Gromacs error

Hi all,
I am getting an error while running with Charmm36 force field in gromacs.

Program: gmx pdb2gmx, version 2020.1-Ubuntu-2020.1-1
Source file: src/gromacs/gmxpreprocess/pdb2gmx.cpp (line 745)

Fatal error:
Atom OT in residue LYS 200 was not found in rtp entry LYS with 22 atoms
while sorting atoms.
.

For more information and tips for troubleshooting, please check the GROMACS
website at Errors - Gromacs

can anyone help me out in this regard?