缺少A# - You should have a A# after your I-140 approval, and you should get
I485 approval next time.
More detail about A#:
The A Number is the Alien Registration Number. The “A” number is used by
the Department of Homeland Security system for the purpose of identifying
aliens. It alone does not serve as employment authorization nor is it
evidence of legal status or permanent residency. After your I-140 approval,
you will be given an A number by USCIS.
Aliens are also often confused Social Security