When you connect fulfillment you need connect one product of InkGo with one product you created with app of fulfillment service. If you can’t find product you can try search with product ID.
Search product ID
1. Go to admin page of your Shopify store.
2. Open menu “products” and find product you want connect.
3. Click cdit product and copy link of product ID from URL.
Ex product url: https:://yourstore.myshopify.com/admin/products/4379955331123, your product ID: 4379955331123
4. From page connect of InkGo, add product ID and search (please view in image)