LAMMPS Simulation NAN Error

I wrote an input script on Cu2CaSnS4 but part of the output is displaying NAN, please I am hereby requesting for your help on how to overcome this problem or better still help me to write a correct input script for this elements.
Thank you

NaNs can have many reasons. errors in the input script, errors in the geometry, bad choice of simulation parameters. best you find somebody local with more experience in MD than you and systematically build your input and system, step by step. perhaps first practice with something simpler until you feel more comfortable with how to run LAMMPS simulations. most certainly, this is not something that can be taught via e-mail.