Nothing published to the /map topic when using SLAM Toolbox (ROS Noetic)

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I’m trying to use the slam_toolbox (https://github.com/SteveMacenski/slam...) on Ubuntu 20.04.4 LTS with ROS Noetic for mapping a Gazebo environment (I usually try the ‘world’ environment) with Turtlebot3.

However, after launching, the slam_toolbox node never publishes anything to the /map topic despite being listed as a subscriber and publisher for the topic. Trying to add the map display to rviz produces a warning with a message, “No map received”.

rqt_graph: https://imgbb.com/r67mpyX TF tree: https://ibb.co/m00KtGv

When I try rostopic echo /map, the output is “WARNING: no messages received and simulated time is active. Is /clock being published?”

I have tried the asynchronous, synchronous and offline methods of the toolbox and I have also tried running some relevant projects from Github (https://github.com/search?q=slam_tool...), but I still run into the same issue.

This is the launch file that I’m using,

<launch>
  <!-- Arguments -->
  <arg name="model" default="$(env TURTLEBOT3_MODEL)" doc="model type [burger, waffle, waffle_pi]"/>
  <arg name="configuration_basename" default="turtlebot3_lds_2d.lua"/>
  <arg name="open_rviz" default="true"/>

  <!-- Gazebo -->
    <include file="$(find turtlebot3_gazebo)/launch/turtlebot3_world.launch" />

  <!-- TurtleBot3 -->
  <include file="$(find turtlebot3_bringup)/launch/turtlebot3_remote.launch">
    <arg name="model" value="$(arg model)" />
  </include>

  <!-- Mapping -->
    <include file="$(find slam_toolbox)/launch/online_async.launch" />

  <!-- rviz -->
  <group if="$(arg open_rviz)"> 
    <node pkg="rviz" type="rviz" name="rviz" required="true" />
  </group>

</launch>

This may not be relevant but after running the launch file, “LaserRangeScan contains 360 range readings, expected 359” is repeatedly published to the terminal. Also calling map_saver, just results in a “ Waiting for the map” output. When I tried launching with turtlebot3_gmapping.launch instead of slam_toolbox, I was able to save the map successfully.

I’m still quite new to ROS so there may be something obvious that I’ve missed here.