Fix a rejected or failed Peppol invoice

A Peppol invoice can fail in three different places: validation before send, addressing (buyer not reachable), or a business reject (IMR) after delivery. Treat them differently. Resending the same number without knowing which failure you have wastes time and often breaks Belgian invoice numbering.

Background on buyer replies: Peppol IMR. Status words on the send: delivery status.

Separate three kinds of “reject”

A red validation report is not a customer saying they will not pay. An IMR reject is not a transport failure. Confusing the two leads people to “overwrite” a delivered invoice.

Step 1: Read the exact status

Capture before you touch numbering:

• Invoice number and whether your ledger already treats it as issued
• Send timestamp and the recipient ID actually used (0208: + enterprise number)
• Exact error code and text (screenshot or export the report)
• Whether the Access Point reported delivered
• If an IMR arrived: status (RE reject, UQ under query, and so on) plus reason code and free text

If delivered, do not “resend the same invoice” until you know whether the buyer rejected it commercially. If not delivered, do not issue a credit note against a document the buyer never received.

Worked example

Atelier Nord SRL prepares F2026-118 for buyer 0208:0987654321.

Case A, validation. The Access Point returns “VAT total does not match the lines” before delivery. The number is not yet issued. Fix VAT mapping, regenerate totals, re-validate, then send. No credit note. See validation errors.

Case B, IMR reject. The same invoice is delivered. The buyer returns IMR Rejected: “PO missing.” Leave F2026-118 as issued. Agree the PO, issue credit note C2026-014 with BillingReference to F2026-118, then send new invoice F2026-119 with the PO. See credit notes on Peppol.

Same invoice number, opposite actions. The status decides.

Step 2: Fix by failure type

Validation errors

Typical causes: missing VAT category, totals that do not reconcile, wrong currency, empty mandatory party fields, invalid unit codes, buyer ID in the wrong scheme.

1. Open the validation report line by line. Fix the first structural error first; later lines often disappear.
2. Correct master data or line items in the draft if the document was never issued in your legal sequence.
3. If the number was already issued, follow Step 3 before inventing a second document.

Content rules: EN 16931 / UBL and Belgian legal mentions.

Addressing failures

1. Re-check the buyer’s enterprise number (ten digits, scheme 0208). Do not put BE0… where the Peppol ID expects 0208 plus the enterprise number.
2. Run participant lookup. Confirm receive capability is published, not only that the number exists in the Crossroads Bank.
3. Confirm legal entity (parent vs subsidiary). A group VAT number is not automatically the right endpoint.
4. If truly off-network, see Client not on Peppol.

Do not “fix” routing by changing random identifiers on a delivered invoice.

Business reject via IMR

Read the reason code and free text. Common themes: wrong PO/reference, price/quantity dispute, wrong buyer entity, tax treatment dispute, missing legal mentions.

1. Agree the commercial correction with the buyer.
2. Issue a credit note (and a new invoice if needed) rather than silently rewriting history.
3. Resubmit only the corrected structured documents. Confirm the buyer’s inbox shows the new CreditNote and, if any, the new invoice.

IMR reject

A structured Invoice Message Response that says the buyer will not accept the invoice as submitted, after Peppol delivery already succeeded.

Step 3: Protect invoice numbering

Belgian invoices need a unique, chronological sequence. Bad patterns:

• Reusing the same invoice number after a failed send that your books already treat as issued
• Deleting a failed number and leaving a gap without a documented policy
• Editing a delivered Peppol XML and resending it as if it were new

When unsure whether the number was consumed, check your invoicing ledger first, not only the Peppol UI. See invoice numbering.

Quick recovery checklist

1. Classify: validation vs addressing vs IMR
2. Fix the root cause once (identity, VAT maths, PO, legal entity)
3. Choose credit / re-issue / resend according to whether the number and delivery already exist
4. Confirm the buyer’s inbox shows the corrected document
5. File the error text and IMR with the invoice for audit

FAQ

Why was my Peppol invoice rejected?

Either validation failed before send, the buyer ID could not be routed, or the buyer sent an IMR reject after delivery. Read the exact status before you resend or credit.

Is a validation error the same as a customer reject?

No. Validation means the structured file failed the rules and was not delivered as a business document. An IMR reject arrives after a successful Peppol delivery.

Can I resend the same invoice number?

Only if the invoice was issued but never delivered and your Access Point plus your books allow retransmission of that document ID. After delivery and a business reject, keep the number and credit, then issue a new invoice.

What should I do after an IMR reject?

Leave the delivered invoice. Agree the correction, send a structured credit note that references it, and a new invoice if a charge remains.

The buyer is not found on Peppol. Is that a reject?

That is an addressing failure, not an IMR. Check 0208 plus the ten-digit enterprise number, run participant lookup, and confirm the legal entity. It is not a reason to edit a delivered invoice.

Should I delete a failed invoice number?

Do not delete a number your ledger already treats as issued. Gaps need a documented policy. If the number was never allocated, fix the draft and use the next number when you send.

Does delivered mean the buyer accepted the invoice?

No. Delivered means the Access Point handed the document over. Acceptance or reject arrives later as IMR, if the buyer sends one.

Do I credit a validation failure?

Not if the invoice was never issued or never delivered. Fix the draft or follow the numbering rules for an issued-but-undelivered document. Credit is for a document that already exists as a sent invoice.