ERROR on proc 0: The ReaxFF parameter file ffield.reax.rdx cannot be opened: No such file or directory (../reaxff_ffield.cpp:69)

Hello, I am using lammps 29 September 2021 version. I am trying to simulate using Reaxx forcefield for my system. However, pair_coeff command is causing the above error.
My input file is as below:

units real
variable cfac equal 1.01325e-4
variable cunits string GPa

atom_style full
boundary p p p

read_data fourbyfour.dat

pair_style reaxff NULL lgvdw yes

pair_coeff * * ffield.reax.rdx C H H H H N N N N N O O

group tkx molecule 10 30

neighbor 2.0 nsq
neigh_modify delay 0 every 1 check yes one 100000 page 1000000

Define minimization parameters

variable etol equal 0.0
variable ftol equal 1.0e-10
variable maxiter equal 1000
variable maxeval equal 1000
variable dmax equal 1.0e-2

Setup minimization style

min_style cg
min_modify dmax ${dmax} line quadratic

######################################

EQUILIBRATION

timestep 0.001
velocity all create 298 12345 mom yes rot no
fix 1 all npt temp 298 298 1 iso 0 0 1 drag 1

Set thermo output

thermo 1000
thermo_style custom step lx ly lz press pxx pyy pzz pe temp
dump tkxfifty tkx atom 1000 tkx888.lammpstkx

Run for at least 10 picosecond (assuming 1 fs timestep)

run 50000

That error message is pretty self-explanatory. Please see pair_coeff command — LAMMPS documentation