Rear camera not working after swapping into new chassis.

I bought a used back case for my phone from iFixIt. I carefully swapped everything over according to the guide. I replaced the battery with a new one and replaced my cracked screen as well. Everything seemed to be working until I went to take a picture. The app opens for half a second and then closes again. I tried all of the fixes online except for the factory reset. I do not believe this to be a software issue, but possibly something I did wrong.

I took the phone back apart but can’t find anything that looks odd or out of place. The thing is, when you transfer the motherboard you don’t even disconnect the camera. However, I did the old “unplug it and plug it back in” anyway. First I unplugged the battery then unplugged and replugged the rear camera, then the battery. Still the phone app simply opens for half a second and then closes.

What could I have messed up? I would just get a replacement camera but I’m very doubtful that would fix it.