unknown identifier in data file

Dear lammps dev

I am using amber2lmp to convert my amber force field to lammps, however the data file face some problem in data file in the first line of Atoms writing. Here is my attachment

data.paa (16 KB)

Try putting a newline before the Masses setting. Also
is the Atoms formatting consistent with the atom_style
you have chosen? This is all documented in the read_data
command doc page.