PDF-08fatal
How to fix PDF-08
The embedded invoice XML has no MIME type
A check of the PDF of a ZUGFeRD or Factur-X invoice, not of its XML. It runs when you upload a PDF; the embedded XML then gets the XSD and EN 16931 checks (XRechnung: also the KoSIT rules). Check your PDF with the ZUGFeRD validator or the Factur-X validator. What the PDF check covers.
What this rule checks
PDF/A-3 requires the embedded file stream to state its MIME type in /Subtype. For the invoice XML it is text/xml.
How to fix it
Set /Subtype /text#2Fxml (the name text/xml) on the embedded file stream.
Related rules
Validate your invoice
Upload your corrected invoice to check it passes PDF-08 and all other ZUGFeRD / Factur-X PDF checks and EN 16931 rules. Free, instant, no signup.