errorEN16931

UBL-SR-52:Document reference shall occur maximum once

Duplicate document reference. Document reference can only appear once in the specified context.

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Why This Error Matters

Invoice will be rejected by EN16931 validators. These structural rules enforce cardinality and conditional requirements. Fix the duplicate element or provide the required companion element.

Common Causes

  • Document reference appears multiple times
  • cac:DocumentReference shall occur maximum once
  • Duplicate document reference in supporting documents
  • Same reference type repeated in BG-24
  • ERP exports multiple identical document references

Frequently Asked Questions

Duplicate document reference. Document reference can only appear once in the specified context.
Duplicate document reference. Document reference can only appear once in the specified context. You can also use Invoice Navigator's automatic Fixer tool to correct this instantly.
Yes, UBL-SR-52 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-52 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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