Invalid security code on debit card????

I had the same error when trying to update my apps on my ipod touch. I tried to input my security code numerous times to no avail. I also made sure my billing address was the same as what my bank had on file. To fix the issue I went into iTunes, logged onto the iTunes store, went to account settings and reviewed my recent purchases. Turned out that I had made a recent purchase and didn't have enough money left on my credit card to pay for it at the time. I paid off the credit card, and then input my security code once more and now it works fine. I've heard that some debit or pay as you go credit cards require a minimum balance, so make sure you have at least that amount in your account.

Read here > iTunes Store: My credit card's security code or zip code does not match my bank's records

I got same problem too. I just bought an apps two days ago but now when I want to add my Credit Card it keep saying that Security code is invaild 😟

That's because it turns out that the limit of your credit card has been reached, that's good even for the free apps you trying to download. A little Apple fail here.