errorubl-2.1

UBL-CR-001:Invalid XML Syntax

The invoice XML is not well-formed. This means the XML structure has errors like unclosed tags or invalid characters.

We can fix this automatically

AUTO-FIX

Auto-fix: Remove the disallowed element from the invoice XML. No data loss occurs because EN16931 explicitly prohibits this element.

No manual changes needed
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Why This Error Matters

Invoice will be rejected by PEPPOL/EN16931 validators. Safe to remove - this element is explicitly prohibited and contains no required business data.

How to Fix It

1

Check for unclosed tags

Every opening tag must have a matching closing tag

2

Validate special characters

Use &amp; for &, &lt; for <, &gt; for >

3

Check encoding

Ensure UTF-8 encoding is declared and used consistently

4

Use XML validator

Run through an XML syntax validator to find exact error location

Code Example

<?xml version="1.0" encoding="UTF-8"?>\n<Invoice xmlns="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2"\n         xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2"\n         xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2">\n  <!-- Properly structured content -->\n</Invoice>

Technical Details

Parser error

Common Causes

  • Source ERP exports full UBL 2.1 instead of EN16931 subset
  • Generic UBL template includes optional elements not needed for e-invoicing
  • Conversion from another format added unsupported elements
  • Manual XML editing introduced non-standard elements
  • Invoice software not configured for EN16931 compliance

Commonly Seen In

Any XML export - manual or automated

Frequently Asked Questions

The invoice XML is not well-formed. This means the XML structure has errors like unclosed tags or invalid characters.
Fix the XML syntax errors indicated by the parser. You can also use Invoice Navigator's automatic Fixer tool to correct this instantly.
Yes, UBL-CR-001 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 UBL-CR-001 can be automatically corrected using Invoice Navigator's Fixer tool. Upload your invoice and the tool will identify and fix common issues, including invalid xml syntax.
UBL-CR-001 is commonly seen in exports from Any XML export - manual or automated. These software packages sometimes generate invoices that need adjustment to meet full compliance standards.

Related Errors

UBL-CR-002

Invalid or Missing Namespace

Last updated: 16 January 2026

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