I’ve been doing this tutorial - YouTube and i can’t figure this issue out. Trigger box makes invisible wall and can’t shoot through it and i can’t make object to simulate physics. Please help me out here fellas, I’m pretty new to this 
You probably have the wrong collision properties set on your trigger box. If it’s meant as a trigger, it should be set to generate overlap events, but not to block anything.
(Note that you have to turn on overlap events, and choose the appropriate collision preset.)
I’m not sure if the normal trigger volumes can be set to simulate physics, because it’s expected that they will stay still, or at least be attached to another object. I’m not sure why you’d want a trigger volume to move on its own, but if you do, you could always use a normal static mesh (set it to invisible if you don’t want the player to see it). Static meshes have collision properties too, so they work perfectly well as trigger volumes.
Generate overlap events is already on, and I’m not sure which collision option is right, i think i tried all of them. Still no luck.
Anyone ?
Help please.
You need to setup your collision presets on your trigger box.
See this collision-filtering article.
Check that your TriggerBox’s ObjectType doesn’t Block your Projectile’s ObjectType.
I ran through the same issue and solved it by opening the projectile blueprint, selecting the Collision Component, and inside its collision settings selecting Overlap for World Dynamic. But then don’t forget to set the enemy’s collision settings accordingly.