Quit the Acrobat application.
In the earlier versions, Acrobat was unable to detect any missing table headers, and such table headers were shown as passed in the Accessibility Checker tool. With the September 2021 release of Acrobat DC (version 21.007.20091), PDFs with missing table headers are flagged in the Accessibility Checker and show as failed in the accessibility check result.
Define the table header tags in the PDF so that the Accessibility Checker does not flag it as a fail in the accessibility check result.
The registry key bypasses the error, and does not flag or fix the missing table header accessibility issue.
In the registry editor, based on your installed version of the product, go to the version-specific location listed below, and modify or create the DWORD key IgnoreTableHeaderCheck,
Add or modify the IgnoreTableHeaderCheck (bool) entry in the com.adobe.Acrobat.FeatureState.plist file: