[Canonman]

Hi Mike,
What has likely happened is a wire from one of the outlets has come loose. There is not usually a junction where wires from the different outlets come together. Rather they are "daisy chained" from one to another. Worse, the manufacturer's have started using a friction connector on the outlets rather than securing the wire under a screw. I'd suggest start with the outlet closest to the distribution panel. Pull it out from the wall and give the wires a good tug. Loose ones will pull out. Keep going until you find the one that is causing your problem. You might pull a couple of loose ones before you find the actual one causing the problem so keep your tester handy.
Good luck!