Atom Type Error in Gromacs

Groamcs Atom Type Error :
gmx grompp -f ions.mdp -c solv.gro -p topol.top -o ions.tpr

Ignoring obsolete mdp entry ‘title’
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 -167936009

Generated 165 of the 1596 non-bonded parameter combinations

ERROR 1 [file UNK.prm, line 5]:
Invalid directive atom types

ERROR 2 [file UNK.prm, line 6]:
Atomtype C834 not found

There was 1 note


Program: gmx grompp, version 2022.3
Source file: src/gromacs/gmxpreprocess/toppush.cpp (line 1437)

Fatal error:
There were 2 errors in input file(s)
topol.top (615.7 KB)