I have an Olympus OM-D camera and a FL-50R external flash. Until tonight flash was working perfectly with OM-D, but tonight when I was sliding the flash on hot shoe it flashed once and after that it refuses to trigger when I was trying to take a picture. Camera recognizes the flash and flash icon appears on display. Flash zooms in and out with lens everything works except that camera does not trigger the flash in any mode. I just cannot figure out what might be wrong.
I'm NOT the expert here, but here are a few thoughts.
Is there a camera dealer near you that would let you try the flash out on an OMD - or other camera for that matter - assuming you don't have that option at home.
Also, you could try cleaning the contacts on flash and the camera hot shoe.
Try removing and replacing the flash battery.
I hope someone else chimes in with a more intelligent suggestion!