Alienware 17 R3 - not charging during game play even though it is plug

When playing games, the computer drains the battery and noticed that the battery is not charging based on the icon at the bottom right, after ignoring it, the 10% windows warning of low bat appeared and it keeps draining because it is not charging. During this scenario, my power adapter is plug-in with lit on. I dont really know what is wrong with the unit because, if you close the game itself, it can charge normally. Im guessing that it doesnt produce power to the battery while charging at a game play.

another thing, contacted chat support and got remote support, he was connected and he was in another session then waited for 20mins. without solving anything. just wasted my time for 20mins.

any thoughts or solutions that i could do it myself? thanks.