I have a Nikon D610 which worked just fine for many years. It has only 15K clicks. When I turn the camera on there is no problem until I take a shot. The picture comes out just fine but after I took a picture the light meter wont show any measurements any more and the camera shows a blinking "Err". When I turn the camera off and back on everything works again. Also I cant seem to enter Live View. Each time I try to I hear the mirror flipping up and back down again. When no lens is attached the problem is literally gone. I can take a burst of shots without any errors and the light meter works all the way through. I can also enter Live View with no lens attached. I already tried different lenses which does not change anything. By the way all my lenses are modern nikon lenses. No third party lenses.
I already cleaned the pins on each lens and also the ones inside the camera. I also flashed the firmware but nothing helps. Do you have any hints?