First remove the battery and ploy in charger and try to power on the unit. If that works the battery is dead and needs to be replaced. If not then your charger is failing and it needs to be replaced.
Google the part number listed on battery and order replacement from Amazon with 30 day return. Test and see if the works.
If not then you have a post broken inside the laptop. You’ll need to take it to a laptop repair person to fix or if your good at soldering order jack replacement and remove defective power plug and put in new plug and solder in. I recommend a professional do this.