# UBL-SR-55

> An Invoice shall contain maximum one Payment Mandate (BG-19).

Checked against Peppol BIS Billing 3.0 2026.5

Canonical: https://einvoicecheck.eu/rules/ubl-sr-55

## Official rule text

An Invoice shall contain maximum one Payment Mandate (BG-19).

## Why did my invoice fail UBL-SR-55?

The Direct debit mandate group (BG-19) holds the mandate reference (BT-89) and the debited account (BT-91) via cac:PaymentMeans/cac:PaymentMandate. EN 16931 permits at most one payment mandate per invoice, since a direct debit is executed under a single mandate.

## Common causes

- cac:PaymentMandate appears in more than one cac:PaymentMeans block.
- A duplicated PaymentMeans element repeats the mandate.
- Two different mandate references were included on one invoice.

## How do I fix it?

```
Include a single mandate: one <cac:PaymentMandate><cbc:ID>MNDT-0099</cbc:ID>...</cac:PaymentMandate>, and remove any duplicates.
```