This means your company (identified by your CBE/VAT number) is already registered on the Peppol network through another Access Point provider. Each company can only have one active Peppol registration at a time.

To resolve this, you need to first transfer your Peppol registration from your current provider to Billdu. Contact your previous provider or Billdu support to initiate the migration. Once the transfer is complete, you can activate e-invoicing through Billdu.

If you delete your Billdu account while your company has an active Peppol registration, your Peppol account is not deleted - it is archived.

If you want to switch to a different invoicing provider, contact Billdu support to arrange the transfer of your Peppol registration to your new provider's Access Point. Your Peppol ID and registration remain intact.

If you later return to Billdu, your account can be unarchived and your Peppol transport recreated.

Mercurius is Belgium's central platform for B2G (business-to-government) e-invoicing, operated by BOSA. It serves as the electronic mailroom for public entities and accepts invoices in Peppol BIS 3.0 format via any accredited Peppol Access Point.

If you invoice Belgian government entities through Billdu, your e-invoices are automatically delivered through Peppol to the Mercurius platform - no additional setup is required on your end.

Source: einvoice.belgium.be - Mercurius