Validation rules
UBL-SR-52 — UBL rule
An invoice line carries more than one cac:DocumentReference — the line-level invoiced-object identifier (BT-128) is allowed at most once.
- Rule
UBL-SR-52— official EN 16931 / XRechnung rule- Severity
- error
- Detected by
- tier 3 — KoSIT validator (authoritative)
- Reachability
- Only reachable when validating your own XML — normbill-generated documents cannot trigger it
The normbill invoice model has no line document reference; generated lines never contain cac:DocumentReference.
How to fix it
Keep a single DocumentReference per invoice line.
UBL-SR-52 auf Deutsch — was bedeutet der Fehler?
Der KoSIT-Validator lehnt die Rechnung ab, weil eine Position mehrere cac:DocumentReference-Elemente trägt — die Objektkennung auf Positionsebene (BT-128) ist höchstens einmal erlaubt.
So beheben Sie den Fehler
Behalten Sie genau eine DocumentReference je Rechnungsposition.
Related rules
UBL-SR-51— An address carries more than one cac:AddressLine — only one additional address line (line 3) is allowed per…UBL-SR-53— A cac:PartyTaxScheme states a TaxScheme/ID but no cbc:CompanyID — the identifier itself (e.g. the VAT…UBL-SR-50— An item carries more than one description (BT-154) — only one cbc:Description per cac:Item is allowed.UBL-SR-54— More than one payment card account (BG-18) is present — cac:PaymentMeans/cac:CardAccount is allowed at most…UBL-SR-49— The tax point date code (BT-8) appears more than once — only one cac:InvoicePeriod/cbc:DescriptionCode is…UBL-SR-55— More than one direct-debit mandate (BG-19) is present — cac:PaymentMeans/cac:PaymentMandate is allowed at…
Official sources
- XRechnung specification (KoSIT / xeinkauf.de)
- KoSIT validator on GitHub and the XRechnung validator configuration
Every 422 from the API lists the rule id, the path in your request JSON, a plain-language message and a suggested fix — see the docs overview for the report format.
Or try it live: drop any XRechnung XML on the free validator — same KoSIT-backed report, no account.