Lg- Optimus Net P690 Not charging and main screen showing to take back off ???

[TLC467]

I have an Lg Optimus net and its not charging and when i plug it in the main screen shows me to lift the back off and i do and have tried to restart it !! I have removed the battery and put the case back on!! can some one tell me how to fix this issue and what is going on!! The phone died and this is what has happened when i try to charge it??