When this happened, had you been doing any shooting in LiveView? I did notice that for some people reporting this error, actually various cameras, there is some common talk about LiveView and when exiting LiveView the mirror doesn’t fully return. In some instances people found that mounting a different lens (I see you have the 18-55) and cycling through LiveView cleared the issue.
By the way, can you repeat the issue “at will”?
It hasn't cleared since it happened. It has not worked at all since. I wasn't using live mode when I was shooting. I had gone from the 18-135 lens to the 55-250. It worked for a couple of hours. I sat the camera down and when I picked it up again an hour or so later it would not get past the error message. I've tried leaving it sit without the battery and then holding down the shutter before putting the battery back in. I also tried going back to the 18-135 lens. Nothing has helped. I don't think it's going to work again without a repair job.