You can find a solution in the "Power System Checkout" guide about your problem. It is on the page no.21-22 of the manual.
However, have you tried charging it with another charger or another port? To identify if there is any problem other than the laptop please follow the below steps.
Step 1: Check if the AC charger is working properly. To do so use another good charger.
Step 2: Try to charge the laptop with a different wall outlet. See if this works or not.
Step 3: You may also give a little bit wiggle to the charging cable to find out if it's lose or not.
Step 4: Also try to check if there is any problem in the electrical board or DC port.
Step 5: In the end , if any of the following does not work please take your laptop to a...