The IOSS number only applies to orders under 150 Euros.
Verify IOSS details on labels
You can confirm the IOSS number is sent correctly by checking these locations:
On the shipment/courier label:
Look for the IOSS badge - a black badge with 'IOSS' written in white
Check under the recipient's address for the IOSS number
On the CN23 document:
Find the IOSS number under the recipient's address
Note: The CN23 document only includes the IOSS number when this document type is used for your shipment.