Waterpik Not Charging

So I plug in my Waterpik to an AC outlet like I’ve always done in the past to charge it, and instead of charging, it doesn’t charge but the power plug gets very warm while plugged in. Why is this happening?

It might need a new battery.

I would suspect a high resistance joint in the plug, probably where the metal from the plug pin is connected to the wiring, if you can change the power cord that would maybe fix the problem…

Great. I just sold off an extra power cord last month.