The seller cannot be identified by any number
The invoice must carry at least one of the seller's three identifiers: the seller identifier (BT-29), the seller legal registration identifier (BT-30) or the seller VAT identifier (BT-31).
Only the issuer holds this value: Factlint reports it and never fabricates it. Test your invoice to find out whether it is affected.
The message your validator prints
Copied verbatim from the sealed artefact: this is the exact sentence the check prints when this rule fails.
[BR-CO-26]-In order for the buyer to automatically identify a supplier, the Seller identifier (BT-29), the Seller legal registration identifier (BT-30) and/or the Seller VAT identifier (BT-31) shall be present.
Quoted from schematron-cen 1.3.16, licensed under EUPL-1.2.
Common searches around this code
These phrases mirror what an integrator searches for: code, syntax, rule, business field and correction.
Test your file with this error in mind
Upload the invoice involved: the report will say whether this code appears, where it appears in the document, and whether Factlint can only report it or also fix it.
To automate this check in an ERP flow, call the validation API and link every returned code to its public page.
Why this error happens
The case shows up with issuers not liable to VAT, who have no number to declare and did not think of filling their legal registration instead. Without one of the three, the buyer cannot match the invoice to any supplier automatically — which is what the rule says in so many words.
How to fix it
Fill the legal registration identifier (BT-30): in France the SIREN or SIRET, in Germany the commercial register number. It is the one of the three that always exists, including without VAT liability.
XML correction example
<ram:SellerTradeParty> <ram:Name>ACME SARL</ram:Name> </ram:SellerTradeParty>
<ram:SellerTradeParty>
<ram:Name>ACME SARL</ram:Name>
<ram:SpecifiedLegalOrganization>
<ram:ID schemeID="0002">552081317</ram:ID>
</ram:SpecifiedLegalOrganization>
</ram:SellerTradeParty>