For those of you who have issues with your camera not connecting with your iPad I just wanted to share a few options. Like may others, I tried clicking the C1 + C2 + photo button etc and also deleting aps and re-adding them etc but I had no luck but I read one forum note that says you should click the reset button on the side of drone which is next to the light on the right side of the drone if the battery is facing you and camera is facing away from you.
Before trying this I was feeling helpless like many of you but I do not like to give up and I do not like paying 100's to some yahoo to guess until it gets fixed so I recommend trying the reset button.... if that alone doesn't work then try doing "all of the above".
The reset button is very small and can be found next to the tiny red/green light near gimball on the right side of drone if battery is facing you and camera is facing away from you.

Hello warehousemaxsim, for the Phantom 3 series, if there is a gimbal disconnected issue, it is recommended to replug the pin cables on the gimbal and relink the drone and RC.