The guy standing on stairs is player and the guy standing at bottom is AI with red traces or lines. The AI is not shooting at the player he is shooting projectiles straight to the ground.
the issue is youre using “Get forward Vector” for your line trace. That gets the forward direction of your enemys blueprint, so unless his whole blueprint is rotated completely up in the air that will never work. Whay you want to do instead, use get actor location on your enemy and your player, use “Find LookAtRotation” drag that out and get forward Vector. That should make the line trace point at your player no matter where he is.