Then learn what to do ! Stop wasting yours and everyone else's time !!!. Most of it is self explanatory but if you're shooting at the Boss/Boss's and its says immune then quit wasting your time and find a Anathema ( the glowing yellow guy ) and kill him and pick up the purple orb called Harmony ( its a buff so you can work on the boss's shield ) it lasts for about 10 seconds. If his shield is still not down then repeat the process until the shield goes down and the hit him with your super. Also if you see all of your team mates working on one boss then help with that boss ( for tier 2/3 ). Don't go one on one with a boss while everyone is working on the other one. Also Revive Revive Revive. A dead guardian is no good to the team when its all timed. Its a waste of time if people don't know what do do when it comes to taking the shields down.