Empty polling results, missing inbound invoices, and duplicate notifications usually trace back to a parameter or configuration mismatch. Check the values listed for each symptom.

No notifications returned when polling

A mismatch on any query parameter returns an empty result without an error. Check that:

• processType is 0 for outbound, 1 for inbound.

• sourceSystemId matches the ERP System ID configured on your endpoint.

Inbound invoices not arriving after endpoint creation

Check the following:

1. Your inbound endpoint is active and your PEPPOL participant identifier is registered in the Slovak SMP. Confirm with your Sovos implementation team.

2. ERP System Communications are configured — you need both an Invoice communication and a Lifecycle communication. Check that both have a plugin selected.

3. The product sk_Invoice_Polling_1.0 is assigned to your organization.

Duplicate inbound notifications

Because autoAcknowledgement=true is configured for Slovakia, notifications are automatically marked as read when your GET request returns them. If you're seeing duplicate deliveries, check whether your inbound endpoint was recently modified or re-created — SMP re-registration can occasionally trigger duplicate deliveries. Use the notificationId to identify duplicates and avoid reprocessing the same document.