Hello I am trying to add test item in sandbox , in order to test sandbox OrderAPI, I created a sandbox test user, and when I am trying to add item, it shows loading state forever, attaching screen:![alt text] : /storage/temp/2522-77.png
Hello @alex_o_32, Basically the Order API is used to purchase items and track the purchase orders.For reference please go through the given doc.
https://developer.ebay.com/api-docs/buy/order/static/overview.html If you want to add item in your sandbox account you have to use either Trading API or Inventory API. Best Regards, eBay Developer Support