This doesn't seem like a sensible reason to show a 0 balance, but maybe I haven't worked in enterprise enough.
My guess: the API is down, so the client attempts to get all coins and their balance and add them up. Because the API errors, no coins are returned, therefore the balance is 0. It's a bad design because its alarming, and I'm fairly sure they're going to change it after this.
It could well be errors caused by an overloaded system.