If your orders are not showing up in OrderCup, please review the troubleshooting tips below.
Enable your WebService Key.
Ensure your WebService key has the All option checked for the resources mentioned in below.
Check to confirm that the WebService key in OrderCup is exactly the same as what you have in your PrestaShop store under Advanced Parameters ⇒ Webservice
You can check the web service key at OrderCup by visiting Settings ⇒ Stores ⇒ Details