I am currently working on a system (beta amyloid 1-16 complexed with zinc2+, pdb id: ize9 , zinc2+ replaced with lead) using the oniom method of gaussian. I set the lead cation as the high layer using dft b3lyp def2qzvpp , and i set the charge to 2 and the multiplicity automatically sets to doublet. I set the remaining of the system to low layer using MM UFF, neutral. The optfreq job finishes in 17 minutes but something pops up, saying, "UNresolvable inconsistency between charge and multplicity and orbital occupancies, orbital data will be ignored."