errorEN16931
UBL-SR-18:Buyer VAT identifier shall occur maximum once
Your invoice contains multiple Buyer VAT identifiers (PartyTaxScheme with VAT scheme). EN16931 allows only one VAT identifier per buyer.
We can fix this automatically
AUTO-FIXAuto-fix: Keep the first occurrence and remove duplicate elements. EN16931 requires exactly one of this element.
No manual changes needed
Upload and Fix NowWhy This Error Matters
Invoice will be rejected by EN16931 validators. These structural constraints ensure consistent processing by receiving systems.
Common Causes
- ERP system exports multiple references where only one is allowed in EN16931
- Data consolidation merged records that should have been deduplicated
- Template or mapping incorrectly configured to output duplicate elements
- Manual editing introduced extra elements
- Invoice conversion from another format did not merge duplicate entries
Frequently Asked Questions
Your invoice contains multiple Buyer VAT identifiers (PartyTaxScheme with VAT scheme). EN16931 allows only one VAT identifier per buyer.
Your invoice contains multiple Buyer VAT identifiers (PartyTaxScheme with VAT scheme). EN16931 allows only one VAT identifier per buyer. You can also use Invoice Navigator's automatic Fixer tool to correct this instantly.
Yes, UBL-SR-18 is a critical error that will cause invoice rejection. It must be fixed before submission to ensure your invoice is accepted.
Many instances of UBL-SR-18 can be automatically corrected using Invoice Navigator's Fixer tool. Upload your invoice and the tool will identify and fix common issues.
See Also
Last updated: 16 January 2026
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