Although I had no problem last time I used this set-up, now I cannot get the 90EX (on my 5DM3) to trigger my off-camera 430EX2 flash. The 90EX does power up and send a flash when I take a picture. I do notice that on my flash function settings on my camera that the Master Flash Firing icon is shaded out. None of the batteries seem to be weak on either flash. Any help would be greatly appreciated. Thanks!
