Get error when launch gazebo_ros empty_world.launch

when I try to launch gazebo_ros empty_world.launch, the code is here: I always get the error, i want to how to solve, thanks. [gazebo-1] process has died [pid 18905, exit code 255, cmd /opt/ros/kinetic/lib/gazebo_ros/gzserver -e ode worlds/empty.world __name:=gazebo __ log:=/home/robot/.ros/log/7719b5f8-4c52-11e9-a3d6-8cec4b9a7b95/gazebo-1.log]. log file: /home/robot/.ros/log/7719b5f8-4c52-11e9-a3d6-8cec4b9a7b95/gazebo-1*.log