Disconnect your phone from the charger first, and then examine the lightning port. What you want to look for is any dirt or lint that could get in the way of the charging process. If you find any, clean the port with a can of compressed air or a toothpick.
It's possible that the issue is caused by the USB cable you're using. See whether you can charge your phone with another Apple-certified USB cord.
If the problem persists, reset your phone while it is still attached to the charger.
- When the red slider displays, press and hold the Sleep/Wake button.
- To turn your gadget entirely off, drag the slider.
- Press and hold the Sleep/Wake button until you see the Apple logo after the iPhone has turned off.
Now issue should be resolve
