Bad iPad charging port

First, give it a reset. Hold down the sleep and home keys until you see the silver apple. Let it reboot and see if that fixes it.

And make sure you are using an iPad charger plugged into the wall. It will show 'not charging' if you are using an iPhone charger or plugging it into USB.

If you are using an iPad charger plugged into the wall then not charging is usually one of four things

Bad outlet

Bad Charger

Bad cable

Swap those out to eitehr rule them out or confirm them as the issue. If it persists beyond that then you may need to take it into Apple and have them take a look at it because the 30 pin charging port can go bad. If your device is still under warranty and there's no obvious signs of 'abuse or neglect' then the malfunctioning port can be covered by the warranty.

1. Try a reset

2. Clean docking port with clean paint brush

3. Try another wall socket

4. Try another cable

5. Try another charger