Fallen order code showing as invalid after trying to redeem?

Hello, I received a Fallen Order code from Twitch Prime a few months ago, and finally have had time to redeem it(trying to play before new game comes out). I enter the code, it registers that it is a fallen order code, then after clicking "confirm" it says "The product code you entered is not valid. Please re-enter the code.". However I know for a fact that this code was never used, I immediately added it to a text file and left it in my pictures folder until I had time to redeem it.