Unknown atom label

Hi there, I’m a new user of the ATAT program, and I’m really sorry for the basic problem that I have. I’m trying to extend the LiMn2O4 structure with 0.5 vacancy on the Li site after extending to a 2x1x1 supercell, but I got an error “Unknown atom label: Li,Vac” after running the command “corrdump -noe -2=3 -3=3 -4=0 -rnd -l=lat.in -s=conc.in > tcorr.out”. I also attached the input file that I used.
conc.in (3.2 KB)
lat.in (1.8 KB)

Really appreciate your help.