ros2 topic echo /tf and ros2 topic echo /odom yield blank

[AtharvaWani3]

I am learning ROS2 and Gazebo. I am using Humble and Gazebo classic 11. I tried running the differential drive example code but it does not resolve the tf in RVIZ.
I also tried ros2 topic echo with /tf and /odom which just return blank. What could be the issue? I made sure all the link names are correct and all indentations and tags are closed.
`

<gazebo reference="base_link">
    <material>Gazebo/Blue</material>
</gazebo>

<gazebo reference="right_wheel_link">
    <material>Gazebo/Grey</material>
</gazebo>

<gazebo reference="left_wheel_link">
    <material>Gazebo/Grey</material>
</gazebo>

<gazebo reference="caster_wheel_link">
    <material>Gazebo/Grey</material>
    <mu1 value="0.1" />
    <mu2 value="0.1" />
</gazebo>

<gazebo>
    <plugin name="diff_drive_controller" filename="libgazebo_ros_diff_drive.so">
        <!-- Update rate in Hz -->
        <update_rate>50</update_rate>
        <!-- wheels -->
        <left_joint>base_left_wheel_joint</left_joint>
        <right_joint>base_right_wheel_joint</right_joint>
        <!-- kinematics -->
        <wheel_separation>0.45</wheel_separation>
        <wheel_diameter>0.2</wheel_diameter>
        <!-- output -->
        <publish_odom>true</publish_odom>
        <publish_odom_tf>true</publish_odom_tf>
        <publish_wheel_tf>true</publish_wheel_tf>
        <odometry_topic>odom</odometry_topic>
        <odometry_frame>odom</odometry_frame>
        <robot_base_frame>base_footprint</robot_base_frame>
    </plugin>
</gazebo>

`