What should I do when it appears like

GROMACS version: 2021
GROMACS modification: Yes/No
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I am trying KALP-15 tutorial with a protein of interest, what should i do if something like below appears?

Generated 165 of the 1596 non-bonded parameter combinations

ERROR 1 [file dppc.itp, line 7]:
Atomtype LC3 not found

There was 1 note

Program: gmx grompp, version 2021.4
Source file: src/gromacs/gmxpreprocess/toppush.cpp (line 1409)

Fatal error:
There was 1 error in input file(s)

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

You have LC3 unknown atom type in the input configuration file. You should add the corresponding force field parameter of that atom type to the force field.

If you have already completed the tutorial, you have a properly constructed force field. If not, then make sure to carefully follow all the indicated steps to incorporate the lipid atom types into the force field. LC3 is a lipid atom type, which means you have not added the parameters for this type to the force field.