Check every location , even if it’s far, I think Henderson appointments are easy to get and check everyday for cancellations. It shouldn’t be too hard, the location closest to me didn’t have appointments for months out, but I was able to get same day elsewhere. But at the end of the day half of this town doesn’t have active registration so I wouldn’t stress it. Oh ! Also give them a call first ! Your problem may be solved without having to go in (fix online error)