Battery Won’t Charge

I have a Latitude 5420 Rugged that I haven’t used in 2.5 years because of my cancer. I used it last weekend and everything was fine. However, when I was using it yesterday I noticed the battery wasn’t charging when I had it plugged in to a working outlet and the battery has now drained to below half power.

The light from the charger is not on and it was on last weekend. All connections are tight. Power outlet is fine. Any suggestions? 🤷🏻‍♂️

Thanks in advance for any assistance. 🙏