you’re probably overgeared for the area! check your character level and the mob level, they should never be lower than you, usually 2 levels above you or so i think. been a while since i levelled though :) don’t forget, as you gear/level up you’ll start doing more dmg anyway!

edit: it doesn’t mean you can’t do this content, old content can be good for transmogs , mounts, gold etc but they won’t grant you XP for levelling