DE-R-019
A Peppol Germany national rule (DE-R-*) – applies when the invoice is sent over the Peppol network to a receiver in Germany.
What this error means
DE-R-019
When both seller and buyer are located in Germany and the payment means code (BT-81) is 58 (SEPA), the payment account identifier (BT-84) must be a valid IBAN.
How to fix it
Check cac:PayeeFinancialAccount/cbc:ID – IBAN without spaces and with a correct check digit.