FCX-04: The XMP fx:ConformanceLevel property does not match the profile actually…
What it means
The XMP fx:ConformanceLevel property does not match the profile actually declared in the embedded CII XML's guideline identifier -- the PDF's own metadata and its embedded invoice disagree about which Factur-X profile this document is.
How to fix it
Set XMP fx:ConformanceLevel to the same profile as the embedded XML's GuidelineSpecifiedDocumentContextParameter/ID (e.g. 'EN 16931', 'BASIC', 'BASIC WL', 'MINIMUM' or 'EXTENDED').