Roblox API UPC.

I have not used Gameflip for quite a few months, and I’m using again but having problems using the API - I’m trying to use it to sell Roblox items but I’m having problems with the UPC. When I run the api to show me the UPC for roblox it comes up with: image and if I put this into my listing and run it then it comes up with an error.

Does anyone know a fix to this? Or what the UPC could be? Thanks.