What it means
For a Greek seller whose address country code is GR, the check applies to each cbc:ID in a cac:AdditionalDocumentReference whose cbc:DocumentDescription equals ##M.AR.K##. The XPath only requires the first character to be a digit from 1 to 9. It does not restrict later characters or detect a missing cbc:ID.
Why it matters
The MARK is intended to be a positive whole number. This limited pattern check can pass even when the value has non-digit characters after its first digit, so passing it does not prove that the whole MARK is correctly formed.
How to fix it
Compare the value with the MARK issued for this document. Enter it in the matching reference's cbc:ID, using digits only, with no leading zero, spaces or added text. If you cannot confirm the MARK, check its source rather than inventing or guessing a number. Check the corrected file again.
Once the file is corrected, check it again for free: Validate a Peppol BIS invoice
Or fix the invoice in a form and download the corrected file, for 1 credit: Fix a rejected e-invoice
The rule as published
Read the rule on the publisher's site
Where this rule applies
| Rule set | Version |
|---|---|
| Peppol BIS Billing 3.0 (invoice) | 2026.5 |
| Peppol BIS Billing 3.0 (credit note) | 2026.5 |
Check your file
Drop your e-invoice to see whether GR-R-004-2 still fails, and which other rules do.