What causes the BR-DE-28 error?

This error occurs when the seller contact email (BT-43) has an invalid format. Common issues include missing @ symbol, spaces in the email, dots at the start or end, or too few characters before/after the @ symbol.

How do I fix BR-DE-28?

Enter a properly formatted email address like kontakt@muster.de. Remove any spaces, ensure there is exactly one @ symbol, and verify the email does not start or end with a dot.

What is a valid email format for XRechnung?

XRechnung requires: exactly one @ symbol, at least 2 characters before and after @, no spaces, no dots at the start or end, and no dot or space immediately before the @ symbol.

Why is email validation so strict?

XRechnung requires machine-readable email addresses for automated processing. Invalid formats would break contact information storage and automated communication systems.

Error codes · XRechnung · Germany

BR-DE-28In your invoicing software

Seller Contact Email Must Have Valid Format

This is the rejection, word for word: „[BR-DE-28] Contact email addresses must be valid email format. The email must contain proper structure with username, @ symbol, and domain. Invalid email addresses fail schema validation.“

XPath: //cac:AccountingSupplierParty/cac:Party/cac:Contact/cbc:ElectronicMail | The seller contact email (BT-43) must contain exactly one @ symbol, with at least 2 characters before and after, no spaces, and no dots at the start or end.

What to have readyNothing. The file has to be re-exported from your invoicing software; we check it again afterwards.

What we doInvoice Navigator automatically fixes this Invoice compliance issue by updating the relevant XML elements (BR-DE-28).

Choose the rejected invoiceor drop it here

XRechnung XML or ZUGFeRD PDF. Checking is free · corrected file €1.90 · the first every 30 days is free · no sign-up.

If you enter it yourself in your invoicing software

Before

<Invoice>
  <!-- Issue: XRechnung requires seller contact email to have valid format -->
</Invoice>

After

<Invoice>
  <!-- Issue resolved per XRechnung (Germany) -->
</Invoice>

Element order is part of the rule: if the element sits in the wrong place, the validator rejects with BR-DE-28.

What the finding looks likeExample

FindingStructure invalid · BR-DE-28

Location//cac:PaymentMeans/cbc:PaymentDueDate

From youA re-exported file

ThenRe-export

ProofSHA-256 and /verify link after the check

Often appears together with

BR-DE-01Invalid Leitweg-ID Format BR-DE-02Payment terms text recommended BR-DE-1Eine Rechnung (INVOICE) muss Angaben zu "PAYMENT INSTRUCTIONS" (BG-16)...