Some US-based workers may be waiting to receive Social Security Numbers (SSNs) from the Social Security Administration; for example, legal permanent residents who are waiting to receive their SSNs. This means that it may be difficult to run a US-based screening since limited data will exist for the candidate.
If they recently came from a non-US country, you can run an international package by selecting the country that the candidate came from as an alternative approach.
Disclaimer: This does not constitute and is not intended to be construed as legal advice. Please consult your legal counsel regarding your compliance obligations and best practices.