Can't buy anything from the Cash Shop.

When I logged on after the server check, I decided I want to revive my pet turkey, but alas, it refused to allow me. I tried on different items, but again, the message was still given.
If you look in the inventory, it clearly shows that I have more than enough room for cash items, (I only have two spots occupied).
Has Nexon made a mistake during the server check, or is there any other factors or theories to account for this problem?