BR-CL-18:Invoice line item tax categories MUST be coded using UNCL5305 code list.
PartyTaxScheme/TaxScheme/ID must be "VAT".
Engine Classification
Normalize VAT category code to valid UNCL5305 value
Confidence: 85% · Applied automatically in pipeline
What is BR-CL-18?
BR-CL-18 is a fatal validation rule defined in the EN 16931 specification. It validates the ID element in the UBL invoice XML.
When this rule fires, the invoice is non-compliant and will be rejected by Peppol access points and national validation services. The sending system receives a rejection response and the invoice does not reach the buyer.
Target path: //cac:ClassifiedTaxCategory/cbc:ID
Why This Error Matters
Invoice rejected. Line-level tax categorization must use standard codes.
BR-CL-18 is a hard failure. Invoices that trigger this rule are rejected at the access point and never reach the recipient. In Peppol networks, this means your sending system receives an MLR (Message Level Response) with a rejection status. The invoice must be corrected and re-sent, adding delay to your payment cycle.
Invoice Navigator can automatically correct this error in your pipeline. The fix is applied with full audit evidence, so your compliance trail remains intact.
Validator Behavior
- ·Causes invoice rejection
- ·Error returned: BR-CL-18
- ·Specification: EN 16931
How to Fix It
Check tax scheme
Find TaxScheme/ID elements
Set to VAT
Must be exactly "VAT"
Before / After
<Invoice> <!-- Issue: Invoice line item tax categories MUST be coded using UNCL530 --> </Invoice>
<Invoice> <!-- Issue resolved per EN 16931 --> </Invoice>
Technical Reference
//cac:ClassifiedTaxCategory/cbc:IDCommon Causes
- ·VAT category code not from UNCL 5305 list
- ·Tax category on line item uses non-standard code
- ·ClassifiedTaxCategory/ID contains invalid value
- ·Tax code from legacy system not mapped
- ·Custom VAT category not in allowed list
Seeing this in production? The API handles BR-CL-18 automatically. See the fix response →
Frequently Asked Questions
PartyTaxScheme/TaxScheme/ID must be "VAT".
Set TaxScheme/ID to "VAT". You can also use Invoice Navigator's automatic Fixer tool to correct this instantly.
Yes, BR-CL-18 is a critical error that will cause invoice rejection. It must be fixed before submission to ensure your invoice is accepted by the recipient's system.
Many instances of BR-CL-18 can be automatically corrected using Invoice Navigator's Fixer tool. Upload your invoice and the tool will identify and fix common issues, including tax scheme must be vat.
See Also
Last updated: 27 February 2026
Handle BR-CL-18 Automatically in Your Pipeline
The compliance engine auto-remediates this error with controlled safety policies and evidence pack generation.