I think you have lost ground somewhere. It can be tough to find. Happened once to me and was actually on the pole. Could also be a lost leg of your 220. Had that just this spring. Even though you are only using 120 you still need 220. To make each leg of 120 work. Mine was at the transformer. Some of my 120 outlets worked some did not. No 220 worked. I'm sure an electrician could explain the how and why of what I'm trying to explain. Most of my experience is with three phase, which is accually easier to troubleshoot.