The Social Security Administration changed the way SSNs were issued in June of 2011. For purposes of verification, this change caused complications.
Facts about the change here: https://www.ssa.gov/employer/randomization.html
When you see the message *unable to determine" the social was issued after June 2011*, that message is created in compliance with the SSN Randomization. We are "unable to determined" the state of issuance and the year of issuance. The concern would be if the names resulting from the trace do not match your candidate.