How do I fix UBL-CR-673?

Invoice Navigator automatically removes the disallowed `cbc:TaxExemptionReason` element from your Invoice (UBL-CR-673). You can also use Invoice Navigator's compliance engine to correct this automatically in your pipeline.

Is UBL-CR-673 a critical error?

Yes, UBL-CR-673 is a critical error that will cause invoice rejection. It must be fixed before submission.

Can UBL-CR-673 be automatically fixed?

Many instances of UBL-CR-673 can be automatically corrected using Invoice Navigator's compliance engine. The fix is applied in your pipeline with full audit evidence.

errorUBL 2.1

`UBL-CR-673`:Disallowed element: cbc:TaxExemptionReason

UBL 2.1 Invoice schema does not include `cac:TaxTotal/cac:TaxSubtotal/cac:TaxCategory/cbc:TaxExemptionReason`. This element must be removed for EN 16931 compliance.

Severity

Fatal

Rule set

UBL 2.1

Country

All EU

Fix type

AUTO-FIX

Confidence

95%

Engine Classification

Remove disallowed UBL element per EN16931 specification

Confidence: 95% · Applied automatically in pipeline

What is UBL-CR-673?

UBL-CR-673 is a fatal validation rule defined in the UBL 2.1 specification. It validates the TaxExemptionReason element under TaxSubtotal > TaxCategory 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: /Invoice/cac:TaxTotal/cac:TaxSubtotal/cac:TaxCategory/cbc:TaxExemptionReason

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Why This Error Matters

Invoice will be rejected by EN16931 validators. These conformance rules prohibit UBL attributes and element combinations not in the EN16931 e-invoicing profile. Remove the disallowed attribute or restructure the element.

UBL-CR-673 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
·Fails UBL schema validation
·Error returned: UBL-CR-673
·Specification: UBL 2.1

Before / After

Failing XML

<cac:TaxCategory>
  <cbc:TaxExemptionReason>value</cbc:TaxExemptionReason>
</cac:TaxCategory>

Corrected XML

<cac:TaxCategory>
  <!-- cbc:TaxExemptionReason removed for EN 16931 compliance -->
</cac:TaxCategory>

Technical Reference

XPath/Invoice/cac:TaxTotal/cac:TaxSubtotal/cac:TaxCategory/cbc:TaxExemptionReason

SpecUBL 2.1

Operationremove

StrategyRemove disallowed UBL element per EN16931 specification

Common Causes

·AdditionalDocumentReference has both object ID and description
·Cannot combine invoice object identifier with description
·Reference must be either object ID or described doc not both
·Document reference structure invalid combination
·ERP exports conflicting reference with description

Seeing this in production? The API handles UBL-CR-673 automatically. See the fix response →

Handle UBL-CR-673 Automatically in Your Pipeline

The compliance engine auto-remediates this error with controlled safety policies and evidence pack generation.

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UBL-CR-673:Disallowed element: cbc:TaxExemptionReason