24 year old was a dependent in 2020, but not in 2021.  His mother received marketplace 2021 Form 1095-A that had both their names & social security numbers on it.  I filed the mother's with no issue, but the son's was rejected.  Unsure why, because there's no penalty if someone doesn't have health insurance.  Here is the rejection notice:

Error Detail:
The e-File database indicates that Form 8962 or a binary attachment with description containing "ACA Explanation" must be present in the return.
Error Resolution:

This return rejected due to Form 8962 Premium Tax Credit missing from the return. In order to complete Form 8962, you should have received Form 1095-A Health Insurance Marketplace Statement with relevant information on the insurance that you purchased in the marketplace.
The ACA Marketplace providers have until 1/31/22 provide the 1095-A to taxpayers. For more information visit https://www.irs.gov/affordable-care-act/individuals-and­families/health-insurance-marketplace-statem....

ANY IDEAS? Thanks!