...
Rule Text: The e-File database indicates that Form 8962 or a binary attachment with description containing "ACA Explanation" must be present in the return.
In order to To correct the error, reference the DataValue (this indicates what person or number the rejection is related to). For more information, regarding how to view the details and data values related to rejections and refusals reference Viewing Reject and Refusals.
...
Someone on the tax return is listed on a Marketplace policy, and the 8962 (Marketplace Insurance) is not included on the tax return.
The taxpayer may be listed on a policy held by a family member or someone in their household , and must report that information (this could require a Shared Policy Allocation).
The IRS has record of the tax customer having a Marketplace Policy, but they did not (fraud, applied for a quote, etc.)
...