This error happens when you attempt to use a UPC/EAN barcode that is tied to an existing item/ASIN and is also already listed in a category that you are not approved to sell in. Verify the barcode number you entered is the exact one we provided as typo's can happen. Entering an existing or incorrect UPC/EAN's are the main causes of this issue. If you have verified you are entering the number correctly and are still seeing this message contact us so that we can trouble-shoot this for you.