In Anthem, there are many enemies that, just like your Javelin, have shields. Unless you deactivate them, that enemy will be invulnerable to your attacks. The blue bar above an enemy's health bar informs you that this opponent has a shield.
There are two types of shields: personal and a dome that surrounds an enemy. Destroying the latter is easier - it doesn't have weak points which means that you can shoot it from any direction. Things you should know about enemies with shields:
- Enemies with a shield are invulnerable to negative statuses (like burning),
- A shield regenerates after some time (or immediately),
- Knock enemies down to extend the time in which their shield regenerates (e.g. use a melee attack after jumping, charge at an enemy while using Colossus's shield, cause explosions, or use abilities that can knock enemies down),
- Elementalists' (enemies that use elements) shield is invulnerable to the element they are using (if you use fire to attack an Elementalist that uses this element, you will deal them 0 damage).
The best way to fight enemies with shields is to reduce their shield slowly and then attack them with the most powerful attacks. Also, remember about knocking enemies down to extend their shield regeneration.