Question, is the camera only 'not working' when you are using a specific app? Or all the time? If only on/with a specific app, then the issue is probably in the app itself. If you recently updated that app, try uninstalling the update. If you haven't updated the offending app, see if there is an update for it.
Besides this, I would suggest you try the following...
1.) Restart the tablet and see if the problem persists?
2.) Clear the Camera app’s cache and data.
3.) Close apps running in the background. Sometimes to many can cause a bit of an overload.
If your device is still under warranty, I suggest not doing anything past here, as it would void the warranty.
4.) The next thing I would try is pulling the battery, leaving it out for a minute or so and then replacing it, to truly restart the device. Yes, I know they don't open easily, which is why you would need to be very careful, and why I said not do to if you are under warranty still.
5.) While you are in there, make sure there are no loose connections. If the connection to that camera has come even a little loose, it can cause this issue.
6. Lastly, if none of the above helps, I would suggest a "Hard Reset" of the device. BUT, before you do that, make sure you back up (to a cloud account, a computer, etc.) all your personal data on the device. Why? Because a "Hard Reset" will wipe the data.
AGAIN PLEASE NOTE: Doing this will clear the data on your tablet, so it is suggested you not choose this option unless you have to, or aren't worried about losing anything on the device.
Be sure you back up any data you want to keep, to a computer or cloud account, before doing the reset.
To "Hard Reset" the tablet...
1. Make sure that the tablet is actually powered off.
2. Press the "Power" and the "Volume Up" buttons, together, until you see the start-up logo on the screen.
3. Once you can see the logo, release the buttons and allow the device to enter the "System Recovery Mode".
4. Next use "Volume Down" button to get to the "wipe data/factory reset" option When in recovery mode the "Volume Up" and "Volume Down" buttons are how to can navigate and highlight what option you need.
5. Once you have selected the "wipe data/factory reset", press the "Power" button to select that option.
6. On the following screen, repeatedly press the "Volume Down" button until the "Yes - delete all user data" option is what is selected.
7. Then press the "Power" button to hard reset the tablet.