What is the issue?
PDF/UA > Logical Structure > Role mapping > Role mapping of non-standard structure types > Non-standard structure type "Story" is neither mapped to a standard structure type nor to another non-standard structure type
What does it mean?
Every non-standard structure type has to be mapped to standard structure type. This mapping is missing in your document.
How to fix it?
Go to the ribbon tab "Logical Structure" in axesPDF QuickFix and use the tool Fix Roles. Map every non-standard structure type to a standard structure type.
For the non-standard structure type "Story" the correct standard type is "Sect".