If the person is an existing customer, you have the ID, and IMHO you cannot deny for unable to verify identification. May try something else, like no current identification available, but as a current customer, they are identified. Current customer = having an existing, not former account. (I know it is mixing up KYC, CIP, ECOA, etc.)
I'd go with osucpa, it may be the license was revoked, or something similar.
Integrity. With it, nothing else matters. Without it, nothing else matters.