The customer is not in the Peppol network: what the error means and what next

In short

• The error arises when the customer is looked up in the network directory: there is no entry for its Peppol ID.
• According to the Financial Administration, the duty to send an e-invoice is fulfilled by sending it through the delivery service, and the error changes nothing about that. Reporting to the Financial Administration takes place regardless of delivery.
• For now, send the customer the same invoice another way and let it know it needs to join.
• An e-invoice is not sent to a consumer (B2C) via Peppol.
• You may send it to a foreign customer voluntarily if it is in the network.

What the error means

When sending, the sender’s access point looks up the customer’s identifier in the Peppol network directory (SML and SMP, explained in the article What is Peppol). If there is no entry, sending ends with an error of the type The participant ID '0245:…' is not registered in the Peppol Network. The Financial Administration describes exactly this case: if the recipient is not registered in the Peppol network (SML), the sending attempt ends with an error because the partner cannot be found in the network (FS FAQ, part II, question 9).

In our portal such an invoice has the status “Undeliverable: the customer is not in the Peppol network”. We accepted the invoice and stored it among the sent ones; if you have a VAT ID, we also report it to the Financial Administration. Nobody can deliver it yet, however, because the customer has not chosen a provider. Via the API the document has the status undeliverable and the webhook receives the event invoice.undeliverable.

Have you fulfilled your duty?

The Financial Administration states (FS FAQ, part II, question 9):

• “From the point of view of the law, the duty to send an e-invoice is considered fulfilled at the moment of its sending through the delivery service.”
• If an error message is returned because the recipient is not registered in the SML, “this fact has no effect on the fulfilment of the sender’s duty”.
• “Reporting to C5 takes place regardless of whether the e-invoice was successfully delivered.”

It answers the question about an unregistered customer similarly: an invoice through the delivery service “will, understandably, end in an error, but you have done everything you could” (FS FAQ, part I, question 42). The report to the Financial Administration is sent only for invoices where the issuer has a VAT ID (FS FAQ, part I, question 44).

According to the FAQ (part I, question 75), a VAT payer that, in the period from 1 January 2027 to 30 June 2030, issues an electronic invoice in accordance with § 85o(2) of the VAT act and sends it through the delivery service under § 76a fulfils its legal duty to issue and send an electronic invoice. Under § 71(5) the customer has the duty to ensure that it can receive an electronic invoice through the delivery service. Non-delivery is therefore not your fault, but you want the invoice paid, so continue with the following steps.

What to do

1. Check the identifier. On /overenie enter the customer’s VAT ID, DIČ or Peppol ID. If you entered a wrong identifier (for example the IČO instead of the DIČ or a typo in the DIČ) or the customer is in the network under a different one, correct it and send the same invoice again with the same number and date of issue, because it has already been handed to the delivery service. Via the API use the same Idempotency-Key.
2. Let the customer know. In the invoice form, for a Slovak customer there is a button “Copy text for the customer” with a ready-made message. A Slovak company joins by selecting a provider on the Financial Administration portal; the procedure is in the article on choosing a postman on the FS portal.
3. Send the same invoice another way. Preferably its XML by e-mail (you may attach the PDF as a preview): a PDF is only an image document, the e-invoice is the structured XML file (FS FAQ, part I, question 3). According to the Financial Administration this is not a new issue but a re-sending of the same electronic invoice by another means (FS FAQ, part I, question 75). Do not therefore issue a new invoice with a different number. You download both the XML and the PDF in the invoice detail. Our portal does not itself send e-mails with invoices outside the Peppol network; if you want to issue and send invoices outside it too, use the tool of one of our intermediaries.
4. After the customer registers, you can send it the same invoice via Peppol again: in the invoice detail download it with the “Download XML” button and send it on the Send from file tab; via the API simply repeat the send with the same Idempotency-Key. If you have the Data archive switched off, we usually delete the content of the document after 14 days, so download the XML right away. The Financial Administration’s FAQ does not expressly comment on re-sending through the network. Whether the customer has joined can again be found on /overenie.

How to prevent it

The invoice form in our portal verifies the customer as soon as you enter its VAT ID or Peppol ID and only unlocks the rest of the invoice once the customer is in the network. If you invoice many customers at once, check them in advance in the section Bulk check of a list of DIČ: you paste a list of DIČ or VAT IDs and receive a table of who is already in the network. The result is as of the morning survey of the network, not a live query, so before sending an individual invoice the check at sending time is decisive.

The customer is a consumer

E-invoicing applies only to invoicing between businesses (B2B) and between businesses and public administration (B2G), not to consumer invoices (FS FAQ, part I, question 4). According to the Financial Administration’s guide for non-governmental organisations, ordinary citizens as consumers are not concerned by mandatory electronic invoicing and invoices may be delivered to them as before, for example by e-mail, by post or via a customer portal. So you send nothing to a private individual via Peppol and the “not registered” error is expected in their case.

Foreign customer

According to the Financial Administration, the eFaktúra system is currently intended only for the exchange of invoices within the Slovak Republic; cross-border sending is planned for a further phase and, according to the current timetable, is expected from 2030 (FS FAQ, part I, question 16). You may, however, voluntarily send an invoice to a foreign customer that is in the Peppol network. Its identifier has the scheme of its country, for example the Czech Republic 9929, Germany 9930, Austria 9914, Hungary 9910 and Poland 9945; a sample document is in sample 13 Foreign customer. If it is not in the network, you invoice it as before.

Common causes of the error

• The SK prefix in the value. Correct is 0245:2121358349; the form 0245:SK2121358349 is a different identifier and delivery to it fails. More in the article on Peppol ID.
• IČO instead of DIČ. A Slovak Peppol ID contains the digits of the DIČ, not the IČO.
• Wrong scheme. Slovak entities must have scheme 0245 with the DIČ, not the older 9950 (FS FAQ, part II, question 23).
• The customer has not completed the selection or has not chosen a provider at all. Until the provider registers it, the network will not find it.
• The customer is in the network but does not accept the given document type. That is a different error from “not registered”. On /overenie you see which documents it accepts. We reject such an invoice before it is handed to the network, so it is neither delivered nor reported to the Financial Administration. When the customer starts accepting the given document type, send it again (via the API with the same Idempotency-Key); if you send it on a different day, the date of issue should be the day of actual sending (FS FAQ, part I, question 74).

Upcoming change: the government bill (print 1454), status on 30 September 2026 in first reading, proposes that the duty to receive electronic invoices should not apply to a taxable person that is not a VAT payer for invoices it is to receive in relation to a lease of real estate exempt from tax under § 38(3), if the real estate is not included in business assets; this would not apply if the person is obliged to receive electronic invoices in relation to other supplies it makes. It is not yet law in force; if adopted, such a customer would not have to be in the network.

Frequently asked questions