REC: Receiver unknown
What it means
Peppol reason REC in an Invoice Response means the party the invoice is addressed to is not known to the receiver.
The usual cause
The buyer named in the invoice, or its identifier, does not match a party the receiver knows.
How to fix it
Check the buyer's name, identifiers and electronic address with the buyer, then send a corrected invoice to the right party if requested.
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 code as published
Read the official document . Source: Peppol BIS Invoice Response 3.1 (BIS 63A), with its code lists, version Peppol BIS 3, 2026-Q2 release, published by OpenPeppol AISBL, read on 8 November 2026.
Klarbon explains each code in its own words; the official wording is in the document linked above.
Look at your file
Check the invoice against the rules this portal applies: Validate a Peppol BIS invoice. Validate a Peppol BIS invoice