# BR-DE-7 Seller contact email must be provided

In XRechnung, the seller contact email address (BT-43) is mandatory within the seller contact group (BG-6). Public procurement invoice platforms in Germany, such as OZG-RE (direct federal administration, more than 170 indirect federal bodies and several Länder) and other state or municipal portals, use this address to automatically send technical status updates, receipt confirmations, rejection notices, and payment advisories.

## Problem Description

> **ERROR**: German XRechnung rule (KoSIT, BR-DE) · XRechnung 3.0

## Context and Significance

An invoice submitted without a valid seller contact email cannot receive automated clearing notices or reject diagnostics from public gateway APIs, prompting immediate Schematron rejection.

## Solution

In your accounting or invoicing configuration, maintain a monitored accounts receivable or billing email address. In UBL 2.1 syntax, populate <cbc:ElectronicMail> inside <cac:AccountingSupplierParty><cac:Party><cac:Contact>. In UN/CEFACT CII syntax, populate <ram:EmailURIUniversalCommunication><ram:URIID> inside <ram:SellerTradeParty><ram:DefinedTradeContact>. Per rule BR-DE-28, the email address must be properly formatted with exactly one @ character and a valid domain name.

- [Validate XML](/en/xrechnung-validator?source=resource&rule=BR-DE-7)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&rule=BR-DE-7)

## Valid Examples

- BT-43 = "rechnungswesen@lieferant.de"
- BT-43 = "billing-support@vendor.com"

## Invalid Examples

- Seller contact group (cac:Contact / ram:DefinedTradeContact) includes name and phone but omits cbc:ElectronicMail / ram:URIID
- Email element contains malformed address without domain (e.g. "rechnung@")

## Code Examples

### Valid XML
```
<cac:Contact>
  <cbc:Name>Finanzbuchhaltung</cbc:Name>
  <cbc:Telephone>+49 30 1234567</cbc:Telephone>
  <cbc:ElectronicMail>rechnung@lieferant.de</cbc:ElectronicMail>
</cac:Contact>
```

### Invalid XML
```
<cac:Contact>
  <cbc:Name>Finanzbuchhaltung</cbc:Name>
  <cbc:Telephone>+49 30 1234567</cbc:Telephone>
</cac:Contact>
```

## Affected Fields

- [BT-43 Seller contact email address](/resources/xrechnung/bt-43-seller-contact-email-address)
- [BG-6 Seller contact](/resources/xrechnung/bt-41-seller-contact-point)
- [BT-41 Seller contact point](/resources/xrechnung/bt-41-seller-contact-point)
- [BT-42 Seller contact telephone number](/resources/xrechnung/bt-42-seller-contact-telephone-number)

## Related Rules

- [BR-DE-2](/resources/kosit-validator-errors/br-de-2-seller-contact-required)
- [BR-DE-28](/resources/kosit-validator-errors/br-de-28-seller-contact-email-syntax)

## Validation Tools

- [Official KoSIT Validator](https://github.com/itplr-kosit/validator): Run the official KoSIT validator with the XRechnung configuration to check EN 16931 and XRechnung rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Find validation errors during conversion and review each correction.

## Related Resources

- [Official Specification](https://xeinkauf.de/xrechnung/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [All validation errors](/resources/kosit-validator-errors): Overview of the EN 16931, XRechnung and Peppol validation rules explained here.