I was flying at civil twilight last night for an hour or so just fine and then when I put in the 4th battery and started up the P4 my screen went black. No error message on the DJI GO 4 app. No image from the camera. I flashed a light near the front of the drone and no image. I also could not switch between photo and video. Any thoughts? I powered it down switched the battery, restarted everything, and no improvement. Also deleted and reinstalled the app....no change. I did not crash the drone or impact it noticably so I don't think I broke anything hardwarewise. It had just flown fine for an hour over three batteries. Appreciate your help in advance.