Equilibration temperature is not achieved according to thermoset temperature

Respected lammps users, I am trying to melt silver on diamond surface with lammps version march, 2022 Here is my script

‘’'# set potential function and parameters

units metal
dimension 3
boundary p p p
atom_style atomic

neighbor 0.5 bin
neigh_modify delay 5

region simbox block -65 143 -1 299 -89 195 units box

lattice fcc 3.567

region substratediamond block -63 141 -85 79 -80 190 side in units box

lattice fcc 4.09

region silver block 2.5 77.5 81 136 30 80 side in units box

create_box 2 simbox

mass 1 12
mass 2* 107.8

create_atoms 1 region substratediamond

create_atoms 2 region silver

group diamondslab region substratediamond

group silvermetal region silver

set group diamondslab type 1
set group silvermetal type 2

pair_style hybrid eam lj/cut 12
pair_coeff 1 1 none
pair_coeff 22 22 eam Ag_u3.eam

pair_coeff 1 2 lj/cut 0.043 3.5

thermo 1
thermo_style custom step lx ly lz press pxx pyy pzz pe temp
thermo_modify norm yes
thermo_modify lost ignore flush yes

#minimize 1.0e-21 1.0e-21 10000 10000
timestep 0.001

velocity silvermetal create 1500 12345 mom no rot no
run 0
velocity silvermetal scale 1500

fix 1 silvermetal nvt temp 1500 1500 0.1
fix 5 diamondslab setforce 0 0 0
#fix 3 diamondslab move linear 0 0 0

dump movie all atom 100 m.flatgroove
run 1100000’‘’

After running the complete simulation the temperature of equilibration is just 68K while I have set it 1500K. When I just try to use any temperature for melting silver only it gets the thermoset equilibration temperature. What is this problem?
Thanks for cooperation

The standard temperature output is for the entire system covering all atoms, but you are only thermalizing the atoms in the group “silvermetal”. So to monitor the evolution of the temperature for that part of the system, you need to either define a temperature compute for only that group, or just access the one that fix nvt already uses. For details, please see the fix nvt documentation.