Error in NPT equilibration (NAN density) after NVT

LAMMPS LAMMPS Beginners
1

Dear all,

I’m a (very) beginner in using LAMMPS.
currently, I am trying to modeling polymer system for preliminary study of LAMMPS.
when I did the NPT equilibration (using Barendsen and 1 bar pressure), there is NAN result for Density value, suddenly from the starting of simulation.
Please provide any suggestion and solution for this error.

For additional information, I used Reaxx FF and temperature at 300 K.

Thank you in advance

2

Impossible without knowing exactly what you did.

That is - by far - too little information.