How to export InDesign Book (indb) to PDF/A
Hello! So I am printing a book that I made in InDesign and the printers requested I send them the book in the PDF/A-1 (ISO 19005-1) standard. However when I try to go to Export Book to PDF, the only standards are the X standards. So I export to PDF/X-1a and open the exported file in Adobe Acrobat. I go to Use Print Production > Preflight > Standards > PDF/A. However I get two errors in my report

I don't know what either of these errors mean and I could not find more information online. I would like to know either if there is a way to export directly to PDF/A in InDesign or if not what these two errors mean and how I can fix them. Thanks!
