EAM alloy and pair hybrid

When I define pair style hybrid to use eam for Al atoms and ZBL for interaction between Al and Ar atoms, I keep getting the pair_coeff error.

pair_style hybrid eam/alloy zbl 1.0 3.0
pair_coeff 1 1 eam/alloy …/…/Al_zope.eam.alloy Al
pair_coeff 1 2 zbl 13 18

pair_coeff 2 2 none

ERROR: Incorrect args for pair coefficients (…/pair_eam_alloy.cpp:52)

Why am I encountering an error with eam/alloy?

What does the eam/alloy doc page say about its pair_coeff usage?