As I understand it it is like this: in your pawns blueprint you have a collision capsule. The collision settings of that capsule matter, not the actual mesh. If you want physics for your mesh you simplify it by adding a physical asset in the Phat editor and apply it to your mesh so you can have ragdolls. Also pay attention to the collision settings which refer to the traces.
You can turn on your collision of your actual mesh though but then you need to turn off the capsule colission otherwhise it may hits the capsule first.
If this doesn’t help you it might be a good idea to start with screenshots of your blueprint and settings.