Hello. I followed this link ,but when I give the command: . ~/catkinws/devel/setup.bash and then roslaunch mytest_gazebo lau.launch the terminal shows me:

nick@nick:~$ . ~/catkin_ws/devel/setup.bash
nick@nick:~$ roslaunch my_test_gazebo lau.launch
... logging to /home/nick/.ros/log/94a4f9f6-b310-11ed-999d-2733cc63783e/roslaunch-nick-40910.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://nick:34619/

SUMMARY
========

PARAMETERS
 * /gazebo/enable_ros_network: True
 * /rosdistro: noetic
 * /rosversion: 1.15.15
 * /use_sim_time: True

NODES
  /
    gazebo (gazebo_ros/gzserver)
    gazebo_gui (gazebo_ros/gzclient)

auto-starting new master
process[master]: started with pid [40924]
ROS_MASTER_URI=http://localhost:11311

setting /run_id to 94a4f9f6-b310-11ed-999d-2733cc63783e
process[rosout-1]: started with pid [40940]
started core service [/rosout]
process[gazebo-2]: started with pid [40943]
process[gazebo_gui-3]: started with pid [40951]
[ INFO] [1677111932.966505637]: Finished loading Gazebo ROS API Plugin.
[ INFO] [1677111932.968208014]: waitForService: Service [/gazebo/set_physics_properties] has not been advertised, waiting...
[ INFO] [1677111933.103305757]: Finished loading Gazebo ROS API Plugin.
[ INFO] [1677111933.104795070]: waitForService: Service [/gazebo_gui/set_physics_properties] has not been advertised, waiting...

What should I do in order to solve this issue? Thanks