# UBL-SR-33

> Supporting document description shall occur maximum once

Checked against Peppol BIS Billing 3.0 2026.5

Canonical: https://einvoicecheck.eu/rules/ubl-sr-33

## Official rule text

Supporting document description shall occur maximum once

## Why did my invoice fail UBL-SR-33?

An Additional supporting document (BG-24) may carry one Supporting document description (BT-123) giving a human-readable explanation of the attached or referenced document. EN 16931 permits at most one description per supporting document, so cbc:DocumentDescription must not repeat inside a single cac:AdditionalDocumentReference.

## Common causes

- Two cbc:DocumentDescription elements in one cac:AdditionalDocumentReference.
- Description duplicated per language within the same reference.
- A template adds a second description line instead of appending to the first.

## How do I fix it?

```
Keep one description per reference: <cac:AdditionalDocumentReference><cbc:ID>DOC-1</cbc:ID><cbc:DocumentDescription>Timesheet March 2026</cbc:DocumentDescription></cac:AdditionalDocumentReference>.
```