What is problem?

I write Al-Mg code
“”"
pair_style eam/fs
pair_coeff * * Al-Mg.eam.fs Al Mg
“”"

but run on windows cmd there are error message.
“”"
ERROR: Incorrect args for pair coefficients (src/MANYBODY/pair_eam_fs.cpp:52)
Last command: pair_coeff * * Al-Mg.eam.fs
“”“”

I pair_coeff * * Al-Mg.eam.fs ““Al Mg””

I think this ““Al Mg”” part is problem, So I try many time by changing that part such as ““Mg Al””, "“Al Al Mg” “Al Mg Mg Mg”. But everything is fail. what problem of that part?

Could it be that you have a total number of atom type that is different from 2 ?