Alienware 18 stops charging

Greetings to everyone!

I've experienced a weird issue on my Alienware 18 and I'm hoping it won't take too long to troubleshoot.

The issue is rather easy to explain. The laptop stops charging and enters battery mode without warning all by itself (I didn't unplug the battery adapter and the battery adapter didn't stop working). If I unplug the adapter from the laptop and plug it back in 5 seconds later, the laptop will again work in power adapter mode and the battery will charge. This lasts a few minutes (~3min) and we're back in the battery mode. I have to unplug and plug the adapter back in constantly.

I've started the Dell support assist program and ran a CPU Stress Test. Even though I had to unplug and plug the charger back in several times, the test passed.

I have the latest BIOS. I'm running Windows 10 with no problem. All drivers installed and working. I could normally play games until this issue. Now the battery mode makes it problematic.

I'll try using the laptop without the battery and see if it will turn off when it usually enters battery mode.