Sky VIP reward code working

[veebee83]

I received an email with a code for a VIP gift as i have been with sky for 15 years. The link in the email takes me to a VIP page where i can select a movie to buy/keep for free using said code. After choosing a movie (Horizon, An American Saga) i put the code in and it then states that the code is not valid for that particular movie.  Any idea why it wouldnt be working?