Validation rules
UBL-SR-28 — UBL rule
The direct-debit mandate reference (BT-89) appears more than once — only one PaymentMandate/cbc:ID per cac:PaymentMeans is allowed.
- Rule
UBL-SR-28— 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 serializer emits at most one PaymentMandate/cbc:ID, from invoice.payment.mandate_id.
How to fix it
Keep a single mandate reference per payment means.
UBL-SR-28 auf Deutsch — was bedeutet der Fehler?
Der KoSIT-Validator lehnt die Rechnung ab, weil die Mandatsreferenz (BT-89) mehrfach vorkommt — nur eine PaymentMandate/cbc:ID je cac:PaymentMeans ist erlaubt.
So beheben Sie den Fehler
Behalten Sie genau eine Mandatsreferenz je Zahlungsweg.
Related rules
UBL-SR-27— A cac:PaymentMeans carries more than one cbc:PaymentMeansCode (BT-81) — each payment means states exactly…UBL-SR-29— The SEPA creditor identifier (BT-90) appears more than once — only one PartyIdentification/ID with schemeID…UBL-SR-26— The payment reference (BT-83) appears more than once in a cac:PaymentMeans — only one cbc:PaymentID per…UBL-SR-30— A document-level allowance carries more than one reason text (BT-97) — only one cbc:AllowanceChargeReason…UBL-SR-25— The deliver-to party name (BT-70) appears more than once — cac:Delivery may carry only one…UBL-SR-31— A document-level charge carries more than one reason text (BT-104) — only one cbc:AllowanceChargeReason per…
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.