I can't use atom indexes larger than 2, is this normal?

Hello all,

I am using the buck/coul/long potential to simulate amorphous silica. I need to use ~7 atom types for the simulation. When using any command to set an atom pair coefficient or in any way modify or create an atom with a larger type than 2, LAMMPS returns the error “Numerical index is out of bounds”. The atoms are loaded via a dump file which has atom types of 1-7, but I have encountered the same problem when declaring each atom manually.

Please help me understand, and thanks!

What is your input?