ERROR: Fix insert/rate/region (id ins): 'start' step can not be before current step (../fix_insert.cpp:573)

Hi, everyone

I face a error when I used the command Fix insert/rate/region, and I don't know what is the reason, anyone could give me some suggestions?

Coupling...
Starting up LIGGGHTS
Executing command: 'run 5 '
run 5
ERROR: Fix insert/rate/region (id ins): 'start' step can not be before current step (../fix_insert.cpp:573)

I list the input as belowe

echo both
log ../DEM/log.liggghts
thermo_log ../DEM/post/thermo.txt

atom_style granular
atom_modify map array
boundary m m m
newton off

communicate single vel yes

units si
processors 1 1 2

# read the restart file
read_restart ../DEM/post/restart/liggghts.restart
region reg cylinder z 0 0 0.014 0.0 0.055 units box
neighbor 0.002 bin
neigh_modify delay 0 binsize 0.01

# Material properties required for granular pair styles

fix m1 all property/global youngsModulus peratomtype 5.e6 5.e6
fix m2 all property/global poissonsRatio peratomtype 0.25 0.25
fix m3 all property/global coefficientRestitution peratomtypepair 2 0.9 0.9 0.9 0.9
fix m4 all property/global coefficientFriction peratomtypepair 2 0.3 0.3 0.3 0.3

# pair style
pair_style gran model hertz tangential history
pair_coeff * *

# timestep, gravity
timestep 0.00001
fix gravi all gravity 9.81 vector 0. 0. -1.
#fix bu all buoyancy level 0.056 dim z density 1000
# walls
fix walls1 all wall/gran model hertz tangential history primitive type 1 zcylinder 0.014 0.0 0.0
fix zwall1 all wall/gran model hertz tangential history primitive type 1 zplane 0.005

# cfd coupling
fix cfd all couple/cfd couple_every 100 mpi
fix cfd2 all couple/cfd/force

region bc cylinder z 0 0 0.0135 0.04 EDGE side in units box
fix pts2 all particletemplate/sphere 15485863 atom_type 2 density constant 2000 radius constant 0.0005
fix pdd2 all particledistribution/discrete 15485867 1 pts2 1.0

#fix ins all insert/pack seed 123457 distributiontemplate pdd2 insert_every 1000 overlapcheck yes vel constant 0 0 -0.00001 particles_in_region 5000 region bc ntry_mc 10000
fix ins all insert/rate/region seed 32452843 distributiontemplate pdd2 nparticles 15000 particlerate 10000 vel constant 0.0 0.0 0.0 insert_every 2000 overlapcheck yes region bc ntry_mc 10000
# apply nve integration to all particles that are inserted as single particles
fix integr all nve/sphere

# output settings, include total thermal energy
#compute rke all erotate/sphere
thermo_style custom step atoms ke vol
thermo 1000
thermo_modify lost ignore norm no
compute_modify thermo_temp dynamic yes

dump dmp all custom 1000 ../DEM/post/dump.liggghts_run id type x y z
run 0