gmx grompp -f ions.mdp -c 3g5d_solv.gro -p topol.top -o ions.tpr  
                      :-) GROMACS - gmx grompp, 2021.5 (-:

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GROMACS:      gmx grompp, version 2021.5
Executable:   /usr/local/bin/gmx
Data prefix:  /usr/local
Working dir:  /home/iiit/work/ccnsb/Kinase/modelling/kinase_paper_modelling
Command line:
  gmx grompp -f ions.mdp -c 3g5d_solv.gro -p topol.top -o ions.tpr

Ignoring obsolete mdp entry 'ns_type'

NOTE 1 [file ions.mdp]:
  With Verlet lists the optimal nstlist is >= 10, with GPUs >= 20. Note
  that with the Verlet scheme, nstlist has no effect on the accuracy of
  your simulation.

Setting the LD random seed to -68173989

Generated 330891 of the 330891 non-bonded parameter combinations
Generating 1-4 interactions: fudge = 0.5

Generated 330891 of the 330891 1-4 parameter combinations

ERROR 1 [file topol_Other_chain_H.itp, line 27]:
  Atomtype C4 not found


There was 1 note

-------------------------------------------------------
Program:     gmx grompp, version 2021.5
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 http://www.gromacs.org/Documentation/Errors
-------------------------------------------------------