The underside of the tail is white tho. How many fox have white under their tails? And it doesn't look long enough or thick (bushy) enought to be neither a fox or coyote.
I think it's a deer, but a smaller one, although not a fawn. That tail just looks too deer-like to me. If it weren't for the tail, I'd guess coyote, but I really believe it's a deer.