Validation rules

NB-IBAN-CHECKSUM

The IBAN fails its checksum — this is almost certainly a typo.

Rule
NB-IBAN-CHECKSUMnormbill pre-flight check (no single official rule id applies)
Severity
warning
Business term
BT-84 — Payment account IBAN
Field in your JSON
invoice.payment.iban

How to fix it

Double-check invoice.payment.iban or invoice.payment.debited_iban against your bank details.

NB-IBAN-CHECKSUM auf Deutsch — was bedeutet der Fehler?

Die IBAN besteht die Prüfziffernkontrolle nicht — mit hoher Wahrscheinlichkeit ein Tippfehler.

So beheben Sie den Fehler

Gleichen Sie invoice.payment.iban oder invoice.payment.debited_iban mit Ihren Bankdaten ab.

NB-* checks run before generation to catch problems the official rule set would only report indirectly. The authoritative KoSIT validation still has the final word on conformance.

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.