Please! particles are falling out of the domain and lost.

Hello everyone,
I am learning how to do simulations by Liggghts. Now, I want two kinds of powders to fall onto the bottom of the domain. But it showed that my particles directly went across the domain and disappeared. I tried to decrease my time step to 1/10, but the problem was still unfixed. Could anyone please help me to deal with this problem? The input script is below. Thanks very much for your help.

atom_style sphere
boundary f f f
newton off
atom_modify map array

communicate single vel yes
units si

processors 2 1 2

region domain cylinder y 0.0 0.0 0.055 0.0 0.085 units box

create_box 2 domain

#read_restart restart/dump1.restart

neighbor 0.0002 bin
neigh_modify delay 0

#Material properties required for new pair styles

fix m1 all property/global youngsModulus peratomtype 1.e9 3.e8
fix m2 all property/global poissonsRatio peratomtype 0.3 0.23
fix m3 all property/global coefficientRestitution peratomtypepair 2 0.64 0.68 0.68 0.64
fix m5 all property/global characteristicVelocity scalar 1.
fix m6 all property/global cohesionEnergyDensity peratomtypepair 2 1.e4 2.e4 2.e4 1.e4
fix m4 all property/global coefficientFriction peratomtypepair 2 0.01 0.05 0.05 0.01
fix m7 all property/global coefficientRollingFriction peratomtypepair 2 0.6 0.8 0.8 0.6

#New pair style
pair_style gran model hertz tangential history cohesion sjkr rolling_friction epsd2
pair_coeff * *

timestep 0.000000001

fix 1 all nve/sphere
fix 2 all gravity 9.81 vector 0.0 -1.0 0.0

#import triangular mesh
fix cad1 all mesh/surface file mesh3/Tmesh1.stl type 1 scale 0.001
fix cad2 all mesh/surface file mesh3/Cmesh2.stl type 1 scale 0.001
fix cad3 all mesh/surface file mesh3/Pmesh3.stl type 1 scale 0.001

#use the imported mesh as granular wall
fix granwalls all wall/gran model hertz tangential history mesh n_meshes 1 meshes cad1

#move the cap
#fix movecad all move/mesh mesh cad1 linear 0.0 0.02 0.0

#group
group nve_group region domain

#distributions for insertion
fix pts1 all particletemplate/sphere 10007 atom_type 1 density constant 7800 radius constant 0.00015
fix pts2 all particletemplate/sphere 10009 atom_type 1 density constant 7800 radius constant 0.00021
fix pts3 all particletemplate/sphere 10037 atom_type 1 density constant 7800 radius constant 0.000285
fix pts4 all particletemplate/sphere 10039 atom_type 1 density constant 7800 radius constant 0.000345
fix pts5 all particletemplate/sphere 10061 atom_type 2 density constant 3200 radius constant 0.00015
fix pts6 all particletemplate/sphere 10067 atom_type 2 density constant 3200 radius constant 0.00021
fix pts7 all particletemplate/sphere 10069 atom_type 2 density constant 3200 radius constant 0.000285
fix pts8 all particletemplate/sphere 10079 atom_type 2 density constant 3200 radius constant 0.000345
###############

fix pdd1 all particledistribution/discrete/numberbased 10091 8 pts1 0.35 pts2 0.35 pts3 0.15 pts4 0.05 pts5 0.045 pts6 0.035 pts7 0.015 pts8 0.005

#region and insertion
region bc cylinder y 0.0 0.0 0.0048 0.05 0.078 units box

#region bc cone y 0.0 0.0 0.005 0.04 0.01 0.08

#region bc block -0.048 0.048 0.0005 0.09 -0.048 0.048

#fix bc all mesh/surface file meshes/platform.stl type 1 move 0. -12. 0. scale 0.08

#particle insertion

fix ins all insert/pack seed 10093 distributiontemplate pdd1 vel constant 0. -1.0 0. &
insert_every once overlapcheck yes region bc ntry_mc 10000 particles_in_region 5000

fix ts all check/timestep/gran 1000 0.1 0.1

compute 1 all erotate/sphere

compute VoroRadius all property/atom radius
variable r2 atom c_VoroRadius
compute voro all voronoi/atom radius v_r2

thermo_style custom step atoms ke c_1 f_ts[1] f_ts[2] vol
thermo 1000
thermo_modify lost ignore norm no

#dump commands
run 1
#

dump dmp all custom 100000 post/die_*.dump id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius
dump dmpstl all mesh/stl 100000 post/dump*.stl

#insert particles
run 50000000

write_dump all custom post-dump/1.dump id type x y z radius

write_restart restart/dump1.restart