Something weird is happening to my 7D Mark II. It has Not been Dropped! Nor Has Gotten Wet! BUT all of a sudden, I will be taking pictures and it shuts off. I have to turn it off and then turn it back on. It is random. It could last an hour of shooting, or it can turn itself off every other photo. The only thing that is different is, the battery grip stopped working. So I took it off, and it was about that time when it started turning itself off. Well, within a couple days. It was my #1 camera for awhile. Still would be my #1 action camera, but I got a Sony A7Riii and it is now my #1, but that Sony cannot focus as fast or as accurate with a signle point focus. In fact that is the one thing I HATE about my Sony is their "Small Spot" is about the size of my 7D's 9-point. So you can forget about shooting through the branches of a bush or tree. That is where my 7D shines and that is why I need to figure out what is going on. But if I have to put out money for a repair. I will just buy a Sony A6000 for $300 and sell all my Canon gear (5D3, 7D2, 70-200, 85, 24-70,etc).
You may simply need a new battery/. Make sure that your battery cover is properly closed, and not damaged. It if pops open just a little bit, this can shut down the camera. The memory card door has a sensor that can shut off the camera, too..
"The only thing that is different is, the battery grip stopped working."
Was this a Canon brand grip? If it was an off brand it could have damaged the internals of the 7D2. Are you using Canon brand batteries? You need to if not. Also could have damaged the internals. Are you using a off brand lens? Remove it and try a Canon lens.
Reset the camera back to factory default settings.
If everything on your 7D2 is Canon brand and still not working even after the reset, I suspect you need to call Canon 1 (800) 652-2666