Code 570: Additional Liability Pending/or Credit Hold - Per IRS Transaction Codes
The IRS is in the process of matching forms they received for you and the ones you reported. Just keep an eye on it; it doesn't mean you're being audited and they should send you a letter if they find something they need more information about.
For more information, please see Section 8A - Master File Codes: https://www.irs.gov/pub/irs-utl/6209-section8a-2016.pdf
