2022-01-05 16:58:02 n162553028781692

pi@raspberrypi:~ $ roslaunch turtlebot3_bringup turtlebot3_robot.launch
... logging to /home/pi/.ros/log/af9d3018-6dfa-11ec-b5f3-b827eb49186e/roslaunch-raspberrypi-1309.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://192.168.0.122:37327/

SUMMARY
========

PARAMETERS
 * /rosdistro: kinetic
 * /rosversion: 1.12.14
 * /turtlebot3_core/baud: 115200
 * /turtlebot3_core/port: /dev/ttyACM0
 * /turtlebot3_core/tf_prefix:
 * /turtlebot3_lds/frame_id: base_scan
 * /turtlebot3_lds/port: /dev/ttyUSB0

NODES
  /
    turtlebot3_core (rosserial_python/serial_node.py)
    turtlebot3_diagnostics (turtlebot3_bringup/turtlebot3_diagnostics)
    turtlebot3_lds (hls_lfcd_lds_driver/hlds_laser_publisher)

ERROR: unable to contact ROS master at [http://192.168.0.249:11311]
The traceback for the exception was written to the log file
================================================================================================

turtlebot 에 bringup 하려고 하니 계속 Error 가 뜹니다.

검색해서 찾아보니 다른 분은 5번 접속 하니 되었다고 하는데

저는 계속 하여도 실행이 안됩니다.

무엇이 문제인지 답변 부탁 드립니다.