What EXACTLY is the rejection message?

Does ProSeries show any "errors", such as you entered a 1095-A but it is missing information?

Why do you think there should be a 1095-A?  Does the taxpayer have insurance through the Healthcare Marketplace?

Unless it is something new, the IRS does not reject an e-file for a missing 1095-A/Form 8962.  They mail a notice to the taxpayer for it.