Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
iTunes Gift Cards Now Redeemable With Camera In iOS 7
Back in November of last year Apple released iTunes 11 with the added functionality of being able to redeem your iTunes gift cards by using your webcam. When searching around iOS 7 beta 1 today I discovered that Apple is now allowing users to redeem their iTunes gift cards and Starbuck app of the week cards by using the camera on your iOS devices.