How do I fix UBL-CR-646?

Invoice Navigator automatically removes the disallowed `cac:SubInvoiceLine` element from your Invoice. You can also use Invoice Navigator's compliance engine to correct this automatically in your pipeline.

Is UBL-CR-646 a critical error?

Yes, UBL-CR-646 is a critical error that will cause invoice rejection. It must be fixed before submission.

Can UBL-CR-646 be automatically fixed?

Many instances of UBL-CR-646 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-646`:A UBL invoice should not include the InvoiceLine SubInvoiceLine

UBL 2.1 Invoice schema does not include `cac:SubInvoiceLine`. 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-646?

UBL-CR-646 is a fatal validation rule defined in the UBL 2.1 specification. It validates the SubInvoiceLine element under InvoiceLine 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:InvoiceLine/cac:SubInvoiceLine

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Why This Error Matters

Invoice will be rejected by EN16931 validators. These conformance rules prohibit UBL elements that are not part of the EN16931 e-invoicing profile. Remove the disallowed element.

UBL-CR-646 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-646
·Specification: UBL 2.1

Before / After

Failing XML

<Invoice>
  <cac:SubInvoiceLine>value</cac:SubInvoiceLine>
</Invoice>

Corrected XML

<Invoice>
  <!-- cac:SubInvoiceLine removed for EN 16931 compliance -->
</Invoice>

Technical Reference

XPath/Invoice/cac:InvoiceLine/cac:SubInvoiceLine

SpecUBL 2.1

Operationremove

StrategyRemove disallowed UBL element per EN16931 specification

Common Causes

·Invoice line contains SubInvoiceLine element
·InvoiceLine SubInvoiceLine not in EN16931 profile
·Nested invoice lines not permitted
·Hierarchical line structure not supported
·ERP exports sub-items within invoice lines

Seeing this in production? The API handles UBL-CR-646 automatically. See the fix response →

Handle UBL-CR-646 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-646:A UBL invoice should not include the InvoiceLine SubInvoiceLine