Seen this question many times
No answers just lots of trials.

Phantom three advanced purchased 1 1/2 years   ago but then crashed and smashed the camera.
Orderd the new camera from B and H  
The camera. RC and AC are connected but never no pic in App.  Grey screen
the RC will not upgrade.  as it will not connect to app.
Also can olny move camera up and down  with RC   and take pictures.
RC GL300a  
tried many cables and different IOS devices.
Lastly AC  had sucessful update with confirmation.

This has to be common and sure would like a Video to correct this.

Thanks   

For the issue you described, it would be best to send it in for a further evaluation by our engineers.
You can submit a case and apply for pickup here: https://repair.dji.com/en/SelfRepair/Area
Since you've done some basic troubleshooting, but still no connection between your phone and remote.