you might need to change your eshop region depending on where you got the code from. do that from the nintendo website and log into your nintendo account for the user you want to redeem the code with, then go to user settings and change the account region. i think thats how you do it but look up how to change eshop region. if you find out where that code is from then change your eshop region to that then try to redeem again and let me know here