[MoveIt]Goal state colliding mistake in RVIZ

Hi, I followed the "Setup Assistant Tutorial" to build a config package for my robo-arm. After that I launched the "demo.launch" of the package moveit_config .I can see the model of my robo-arm.But when I move the Interactive Marker.It seems that the goal state colliding detecting mistake. The links far from each other obviously turned red color. I need your help.Thank you !!