BR-CO-26
A rule of the European standard EN 16931 – applies to every invoice following the standard, including Peppol BIS Billing 3.0.
What this error means
BR-CO-26
The seller has no identifier at all: neither seller ID (BT-29), nor legal registration ID (BT-30), nor VAT ID (BT-31). The buyer cannot identify the supplier automatically.
How to fix it
Add at least the company registration code or the VAT identifier to the seller party.