Validation rules

UBL-SR-55 — UBL rule

More than one direct-debit mandate (BG-19) is present — cac:PaymentMeans/cac:PaymentMandate is allowed at most once.

Rule: UBL-SR-55 — 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, from invoice.payment mandate fields.

How to fix it

Keep a single PaymentMandate in the document.

UBL-SR-55 auf Deutsch — was bedeutet der Fehler?

Der KoSIT-Validator lehnt die Rechnung ab, weil mehrere Lastschrift-Mandate (BG-19) vorhanden sind — cac:PaymentMeans/cac:PaymentMandate ist höchstens einmal erlaubt.

So beheben Sie den Fehler

Behalten Sie genau ein PaymentMandate im Dokument.

Related rules

UBL-SR-54 — More than one payment card account (BG-18) is present — cac:PaymentMeans/cac:CardAccount is allowed at most…
UBL-SR-53 — A cac:PartyTaxScheme states a TaxScheme/ID but no cbc:CompanyID — the identifier itself (e.g. the VAT…
UBL-SR-52 — An invoice line carries more than one cac:DocumentReference — the line-level invoiced-object identifier…
UBL-SR-51 — An address carries more than one cac:AddressLine — only one additional address line (line 3) is allowed per…
UBL-SR-50 — An item carries more than one description (BT-154) — only one cbc:Description per cac:Item is allowed.
UBL-SR-49 — The tax point date code (BT-8) appears more than once — only one cac:InvoicePeriod/cbc:DescriptionCode is…

Official sources

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.