Mistake 1: Wrong or missing Peppol ID
The most common mistake when sending a Peppol invoice is using the wrong Peppol ID for the recipient. Each business has a unique identifier on the Peppol network, typically based on their enterprise number or VAT number.
Why it happens
Confusion often arises because businesses may have multiple identifiers: a VAT number (BE0XXX.XXX.XXX), an enterprise number (0XXX.XXX.XXX), and a Peppol ID (0208:0XXXXXXXXX). Using the wrong format or an outdated identifier leads to delivery failure.
How DEMFACT prevents it
DEMFACT automatically looks up your client's Peppol ID in the Peppol directory when you create an invoice. If the client is registered, DEMFACT uses their verified Peppol ID. If they are not found, you are notified before sending, preventing failed deliveries.
Mistake 2: Missing mandatory fields
Peppol invoices must contain all mandatory fields as defined by the Belgian and European UBL specifications. Missing even one required field causes the invoice to be rejected by the network.
Commonly missing fields
- Payment means (how the invoice should be paid)
- Tax category codes for each line item
- Buyer reference or order reference (required by some recipients)
- Due date
- Currency code
How DEMFACT prevents it
DEMFACT's invoice form includes all mandatory fields and validates them before sending. If a required field is empty or invalid, you see a clear error message explaining what needs to be corrected. It is impossible to send an incomplete invoice through DEMFACT.
Mistake 3: Incorrect VAT calculations
VAT calculation errors are surprisingly common, especially when invoices contain multiple line items with different VAT rates. Rounding errors, incorrect subtotals, and wrong rate application can all cause Peppol validation failures.
Common calculation errors
- Applying the wrong VAT rate to a line item
- Rounding VAT amounts incorrectly (Belgian rules specify rounding to 2 decimal places per tax category)
- Mismatches between line-level and invoice-level totals
- Forgetting to apply 0% rate for intra-Community supplies
How DEMFACT prevents it
DEMFACT performs all VAT calculations automatically using Belgian-compliant rounding rules. Line totals, tax amounts per rate, and grand totals are calculated and cross-verified before the UBL document is generated. Mathematical errors are impossible.
Mistake 4: Wrong UBL format or version
Peppol in Belgium requires the UBL 2.1 format with specific Belgian customisations (PINT billing). Using an older UBL version, a different format (like CII), or missing the Belgian profile causes rejection.
Why it happens
Businesses using generic invoicing software that was not designed for the Belgian market sometimes generate invoices in the wrong format. Software that supports Peppol in one country may not have the correct Belgian profile configured.
How DEMFACT prevents it
DEMFACT generates UBL 2.1 documents with the correct Belgian Peppol profile every time. Since DEMFACT was built specifically for Belgium, the format is always correct. You never need to worry about UBL versions or profile identifiers.
Mistake 5: Not checking delivery status
Many businesses send a Peppol invoice and assume it was delivered successfully. Without checking the delivery status, they miss failed deliveries and do not follow up, leading to delayed or missed payments.
Why it matters
Delivery failures can occur for various reasons: the recipient's Access Point may be temporarily down, their Peppol registration may have expired, or there may be a routing issue. If you do not check, you may not realise the invoice was never received.
How DEMFACT prevents it
DEMFACT's Peppol outbox shows the delivery status of every invoice in real time. You can see at a glance which invoices were delivered, which are pending, and which failed. For failed deliveries, DEMFACT provides the specific error and guidance on how to resolve it.
Mistake 6: Ignoring incoming Peppol invoices
Since the mandate requires businesses to receive Peppol invoices, ignoring your Peppol inbox can lead to missed invoices, late payments to suppliers, and strained relationships.
Why it happens
Some businesses register on Peppol for sending but forget that they also receive invoices through the network. Without regularly checking their Peppol inbox, supplier invoices accumulate unprocessed.
How DEMFACT prevents it
DEMFACT notifies you when new Peppol invoices arrive. Incoming invoices appear in your inbox with all details pre-extracted and ready for review. You can view, download, and forward them to your accountant directly from the platform.
Mistake 7: Not registering on time
Some businesses delayed their Peppol registration, thinking the mandate would not be strictly enforced. As a result, they were unable to receive invoices from suppliers who had already switched to Peppol-only invoicing.
Consequences of late registration
- Missing supplier invoices sent via Peppol (they bounce back to the sender)
- Delayed payments and disrupted supply chains
- Potential fines from the tax administration
- Need to request re-sends of bounced invoices once registered
How DEMFACT prevents it
Registration on the Peppol network through DEMFACT takes minutes, not days. If you have not registered yet, do it now. Create your DEMFACT account, complete the Peppol registration, and you will be ready to send and receive e-invoices immediately.
How to avoid all these mistakes
The simplest way to avoid all seven mistakes is to use a platform that was purpose-built for Belgian Peppol e-invoicing. DEMFACT validates every field, calculates every amount, formats every document, tracks every delivery, and manages your entire Peppol workflow — so you can focus on running your business.
Create your free account today and send error-free Peppol invoices from the start.
