# BR-01 — Specification identifier missing

> https://billhorse.com/en/rules/br-01/

## What does this error mean?

Without the CustomizationID (BT-24) the profile (XRechnung, Factur-X …) cannot be determined.

## How to fix it

Set the URN matching the target specification, e.g. urn:cen.eu:en16931:2017#compliant#urn:xeinkauf.de:kosit:xrechnung_3.0.