Document fragment not inserting into main document header or footer

Problem

When using a document fragment for a header or footer, the document fragment is not being inserted into the generated document.

Overview

The reason why the document fragment is not being inserted into the header/footer of the generated document, is because the content within the fragment is in the header/footer as well. A good way to think about it is that you cannot have a header within a header or footer within footer, but you can have a body within a header or footer.

Solution

Open up the fragment, which you have uploaded into the content library, and cut/paste the content from the header or footer into the body of the fragment. Once complete, upload the fragment, re-approve and test the output document.