Dear MD users,

I would like to perform an MD simulation of water diffusion in FER Zeolite using gromacs. in the first step, I downloaded in CIF file of FER from IZA and extended in (3*3*6) directions.

As a first try, I would like to equilibrate just the FER structure (Without water) In the NPT and NVT level. But in the mdrun level of both NPT and NVT I faced with this erro :

ERROR 1 [file npt.mdp]: The largest distance between excluded atoms is 6.218 nm, which is larger than the cut-off distance. This will lead to missing long-range corrections in the forces and energies.

What is the main reason? the system is so simple and I just made the structure with Materials Studio. I attached necessary files here.

I would appreciate if any body help me with this error.

Thanks