Exterior light fixture: White wire hot, black wire not,

I have an outdoor flood light fixture that stopped working. I don’t use it often so it could have stopped working at any time.

I changed the bulbs and that didn’t work, so I got a new fixture.
I took down the old fixture, then checked the wires (one black, one white, no ground was attached) with a proximity volt detector. It showed there was voltage in the white wire and none in the black wire.

I tried hooking up the new fixture with black on black and white on white and the light would not work. I tried black on white and white on black and still the light did not work although the voltage detector still showed a charge.

There are several lights on the same circuit with two way switches and a couple out keys. I checked the outlets with a receptacle tester and they show as being normal. The switches seem to be wired correctly.

I have not pulled down the interior light fixtures to examine them yet.

Any clues as to what is going on?