Collision does not work with Actors that are attached to other Actor

I want to Attach a already in Editor spawned (Blueprint) Box to the Player Character so the Player can move the Box around.
Attaching, Moving etc works already. i also can jump on the box etc, but as soon i Attach the Box and move it to a wall it gets in wall
and the pawn Cabsule Collision is the thing where Collision is, Box seems not to colide. U know how i can set it up to Colide with my walls ?
Should be World Static, i already set this to the Mesh but it has no collision after Attaching Box Actor to my Character Actor.

Thx for ur answer