This topic has been covered quite a bit, as you may want to research previous postings regarding the issue, but once again many have found it necessary to try various approaches to resolve this particular concern.
You may try rebinding the camera, a process described in your manual, or deleting and re-installing the camera App. Generally, when the screen on your device is grayed or blacken out you may find it necessary to replace the Wi-Fi Transmitting module to resolve the issue.
I personally found I was unable to take video or photo's and received messages such as "Network had timed out". Although I was still able to control the camera tilt functions, the initial image taken by the camera upon start up of the camera App. had been frozen onto my tablet screen.
End result, I found it necessary to replace my camera. Good Luck!