What it means
When the seller has a tax representative (BG-11), the tax representative's VAT number (BT-63) may appear only once. In UBL it is the cbc:CompanyID inside cac:PartyTaxScheme, so the rule fails when the tax representative has more than one such entry.
Why it matters
EN 16931 allows at most one VAT number for the seller's tax representative.
How to fix it
Check the tax representative details in your invoicing software and keep one VAT number. Delete the second number, or the second tax entry if your software lists them separately, and export again. In the XML, cac:TaxRepresentativeParty may contain at most one cac:PartyTaxScheme/cbc:CompanyID.
Once the file is corrected, check it again for free: Validate an invoice against EN 16931
Or fix the invoice in a form and download the corrected file, for 1 credit: Fix a rejected e-invoice
The rule as published
Seller tax representative VAT identifier shall occur maximum once, if the Seller has a tax representative Where this rule applies
| Rule set | Version |
|---|---|
| EN 16931 (UBL) | 1.3.17 |
| EN 16931 (UBL credit note) | 1.3.17 |
| XRechnung 3.0 (UBL) | 3.0.2 |
| XRechnung 3.0 (UBL credit note) | 3.0.2 |
| Peppol BIS Billing 3.0 (invoice) | 2026.5 |
| Peppol BIS Billing 3.0 (credit note) | 2026.5 |
| SI-UBL 2.0 / NLCIUS (invoice) | 2.0.3.13 |
| SI-UBL 2.0 / NLCIUS (credit note) | 2.0.3.13 |
| France CTC (UBL invoice) | 1.4.0-04 |
| France CTC (UBL credit note) | 1.4.0-04 |
| CIUS-RO UBL Invoice 1.0.9 | 1.0.9 |
| CIUS-RO UBL Credit Note 1.0.9 | 1.0.9 |
Check your file
Drop your e-invoice to see whether UBL-SR-23 still fails, and which other rules do.
Related rules
- UBL-SR-24 An invoice can have only one set of delivery details
- UBL-SR-25 A delivery party needs exactly one name
- UBL-SR-26 A payment block can have only one payment reference
- UBL-SR-27 Only one payment means code per payment block
- UBL-SR-28 A payment block can have only one mandate reference
- UBL-SR-29 Only one SEPA creditor identifier is allowed in the invoice