# BR-DE-7 — Contact e-mail missing (XRechnung)

> https://billhorse.com/en/rules/br-de-7/

## What does this error mean?

The seller contact e-mail (BT-43) is mandatory in XRechnung.

## How to fix it

UBL: Contact/ElectronicMail. CII: EmailURIUniversalCommunication/URIID.