Can't avoid collisions with obstacles in Moveit

I defined the URDF model for my robot and then I'm using moveit for planning trajectories. Everything seems to be working well but when I add objects as obstacles, the robot doesn't avoid the collision with this (attachment files), even it doesn't avoid the collisions with itself. However the collisions are shown in red when planning. [collision.png](/upfiles/14394239328741415.png) [collision1.png](/upfiles/14394239514459194.png) Thank you