[ERROR] [launch]: process[gazebo-1] process has died [pid 75378, exit code 255, cmd 'gazebo --verbose -s libgazebo_ros_factory.so'].

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Hello, I am new to the gazebo, after installing ROS2 and gym-gazebo2 while I try to run an example I get the following error, can someone help me with it?

    duttonide@ubuntu:~/ros2learn/experiments/examples/MARA$ ros2 launch mara_gazebo mara.launch.py --urdf mara_robot_gripper_140

    [INFO] [launch]: process[gazebo-1]: started with pid [75378]
    [INFO] [launch]: process[robot_state_publisher-2]: started with pid [75379]
    [INFO] [launch]: process[spawn_mara.py-3]: started with pid [75380]
    [INFO] [launch]: process[hros_cognition_mara_components-4]: started with pid [75381]
    Initialize urdf model from file: /home/duttonide/ros2_mara_ws/install/share/mara_description/urdf/mara_robot_gripper_140.urdf
    Parsing robot urdf xml string.
    Link table had 1 children
    Link base_link had 1 children
    Link base_robot had 1 children
    Link motor1_link had 2 children
    Link motor1_cover had 0 children
    Link motor2_link had 1 children
    Link motor3_link had 2 children
    Link motor3_cover had 0 children
    Link motor4_link had 1 children
    Link motor5_link had 2 children
    Link motor5_cover had 0 children
    Link motor6_link had 3 children
    Link ee_link had 0 children
    Link tool0 had 0 children
    Link gripper_adapter had 1 children
    Link robotiq_adapter_link had 1 children
    Link robotiq_arg2f_base_link had 4 children
    Link right_outer_knuckle had 1 children
    Link right_outer_finger had 1 children
    Link right_inner_finger had 0 children
    Link left_inner_knuckle had 0 children
    Link left_outer_knuckle had 1 children
    Link left_outer_finger had 1 children
    Link left_inner_finger had 0 children
    Link right_inner_knuckle had 0 children
    got segment base_link
    got segment base_robot
    got segment ee_link
    got segment gripper_adapter
    got segment left_inner_finger
    got segment left_inner_knuckle
    got segment left_outer_finger
    got segment left_outer_knuckle
    got segment motor1_cover
    got segment motor1_link
    got segment motor2_link
    got segment motor3_cover
    got segment motor3_link
    got segment motor4_link
    got segment motor5_cover
    got segment motor5_link
    got segment motor6_link
    got segment right_inner_finger
    got segment right_inner_knuckle
    got segment right_outer_finger
    got segment right_outer_knuckle
    got segment robotiq_adapter_link
    got segment robotiq_arg2f_base_link
    got segment table
    got segment tool0
    got segment world
    Couldn't set scheduling priority and policy: Operation not permitted
    node_name hros_cognition_ubuntu
    Adding fixed segment from world to table
    Adding fixed segment from table to base_link
    Adding fixed segment from base_link to base_robot
    Adding moving segment from base_robot to motor1_link
    Adding fixed segment from motor1_link to motor1_cover
    Adding moving segment from motor1_link to motor2_link
    Adding moving segment from motor2_link to motor3_link
    Adding fixed segment from motor3_link to motor3_cover
    Adding moving segment from motor3_link to motor4_link
    Adding moving segment from motor4_link to motor5_link
    Adding fixed segment from motor5_link to motor5_cover
    Adding moving segment from motor5_link to motor6_link
    Adding fixed segment from motor6_link to ee_link
    Adding fixed segment from motor6_link to tool0
    Adding fixed segment from motor6_link to gripper_adapter
    Adding fixed segment from gripper_adapter to robotiq_adapter_link
    Adding fixed segment from robotiq_adapter_link to robotiq_arg2f_base_link
    Adding moving segment from robotiq_arg2f_base_link to right_outer_knuckle
    Adding fixed segment from right_outer_knuckle to right_outer_finger
    Adding moving segment from right_outer_finger to right_inner_finger
    Adding moving segment from robotiq_arg2f_base_link to left_inner_knuckle
    Adding moving segment from robotiq_arg2f_base_link to left_outer_knuckle
    Adding fixed segment from left_outer_knuckle to left_outer_finger
    Adding moving segment from left_outer_finger to left_inner_finger
    Adding moving segment from robotiq_arg2f_base_link to right_inner_knuckle
    [INFO] [hros_cognition_ubuntu]: HROSCognitionMaraComponentsNode::on_configure() is called.
    ====================== Reading link order ======================
    topic name: /hrim_actuator_rotaryservo_000000000001/trajectory_axis2
    topic ...