KSEF-NS-DRAFT
A check of the Polish KSeF FA(3) system – applies to invoices submitted to KSeF; a separate format, not Peppol.
What this error means
KSEF-NS-DRAFT
The invoice uses the withdrawn FA(3) draft namespace (2025-04-03), which is still floating around the web. Production KSeF accepts only the final FA(3) namespace.
How to fix it
Change the namespace to http://crd.gov.pl/wzor/2025/06/25/13775/ or regenerate the invoice with updated software.