# BR-DE-6 — Contact phone missing (XRechnung)

> https://billhorse.com/en/rules/br-de-6/

## What does this error mean?

The seller contact phone number (BT-42) is mandatory in XRechnung.

## How to fix it

UBL: Contact/Telephone. CII: TelephoneUniversalCommunication/CompleteNumber.