The camera stopped working. and every time I go on the camera it says camera error ,couldn't connect to the camera

First try restarting the tablet.

Then try logging out of your Samsung account and logging in again.

If that doesn't work, try installing a different camera app from the Play Store (Open Camera is pretty good).

Try connecting it with pressing the wps on your router and on your tablet select the wps

That means to connect your charger

Happened to me today with a Nexus 5; I rebooted the phone, the error went away.

Mine has stopped working as well. I did as restore, deleting everything. Don't bother. It didn't fix it. I am calling Hannspree today and will post here if there is a solution,

sounds like the camera it's self has quit IE hardware problem, this is not uncommon, still under warranty.

I'm not that good with android tablets, but is there a way you can remove the battery? and then replace the battery after a little while?
When some app is blocking mother one, you should try to reset the tablet and start from scratch. Try to close apps when you no longer use them.

In my case was just an app. "Lantern" - flashlight using LED...after uninstal that "s*tty" app the camera was OK again.

Have you checked the app you are using has the 'Enable Camera' setting ticked in it's settings? Soz if that sounds silly but you'd be suprised how many 'setting's decide to change themselves for no reason.
Make sure you have enough free memory on the phone. Move as many personal files such as music and saved videos etc. from phone memory to the Ext. SD Card (external sd card)
Can you take pictures or video with the camera? If so the problem is with the video call app you are using (skype etc) uninstall it (remove the app) and reinstall from app store.
Did you notice the problem started after installing another app?? Installation of another app might be interfering with it also. Try video call after re-boot before opening up any other apps.

I supose this old problem has been solved?