What it means
When an invoice carries an attachment inside the file (BT-125), the attachment declares its file type as a MIME code (BT-125-1). Peppol accepts only six: application/pdf, image/png, image/jpeg, text/csv, application/vnd.openxmlformats-officedocument.spreadsheetml.sheet (an XLSX spreadsheet) and application/vnd.oasis.opendocument.spreadsheet (an OpenDocument spreadsheet). Anything else fails, for example a Word file, a ZIP archive or an XML file, and so does a code with capital letters such as Application/PDF. The check reads the declared code, not the file itself.
Why it matters
Peppol BIS Billing 3.0 requires the declared MIME code of an embedded attachment to be on its allowed list.
How to fix it
Convert the attachment to a PDF, PNG, JPEG, CSV, XLSX or OpenDocument spreadsheet file and add it again, or remove it if the buyer does not need it. If the file type is fine and only the code is wrong, correct it in your invoicing software. If you build the XML yourself, the code is the mimeCode attribute of cbc:EmbeddedDocumentBinaryObject, for example mimeCode="application/pdf".
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 PEPPOL-EN16931-CL001 still fails, and which other rules do.
Related rules
- PEPPOL-EN16931-CL002 Discount reason code must be on the allowed list
- PEPPOL-EN16931-CL003 Charge reason code must be a valid UNCL 7161 code
- PEPPOL-EN16931-CL006 The VAT point date code must be 3, 35 or 432
- PEPPOL-EN16931-CL007 Amounts must use a valid ISO 4217 currency code
- PEPPOL-EN16931-CL008 Electronic address scheme must be on the Peppol code list