I tried that as well but couldn't toggle as described in the forum, but did stumble upon the answer with the display disable/enable choice in the menu screen. Not sure how I turned it off in the first place though, but it doesn't matter now.
I came here looking for a solution after encountering the same problem. For me, the answer had nothing to do with camera settings. I read this message and discovered that the eyepiece on my camera had somehow gotten loose and shifted up just enough to cover the sensor but not enough for me to notice. I slid it back down with a satisfying click, saw the sensor it had been blocking, and the problem was resolved.