robot_description not found on parameter server while launching the controller.

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Hello everyone, I have one own created controller for one crane arm. Here you can find the necessary information from controller yaml file,

hardware_interface:
  joints:
    - neck_L_j1
    - arm_j1_j2
    - arm_j2_j3
  sim_control_mode: 1 # 0: position, 1: velocity

# Publish all joint states -----------------------------------
joint_state_controller:
    type: joint_state_controller/JointStateController
    publish_rate: 500  


crane_left_eff_pos_controller:
     type: effort_controllers/JointGroupPositionController
     joints:
       - neck_L_j1
       - arm_j1_j2
       - arm_j2_j3

     neck_L_j1:
       pid: {p: 3000.0, i: 1.0, d: 0.01}
     arm_j1_j2:
       pid: {p: 3000.0, i: 1.0, d: 0.01}
     arm_j2_j3:
       pid: {p: 3500.0, i: 1.0, d: 0.01}

I have created the controller launch file which contains the following information.

<?xml version="1.0"?>
<launch>
<group ns="/robot1">
    <rosparam file="$(find crane_arm_controller_robot1)/config/crane_arm_controller.yaml" command="load" />

    <arg name="controllers" default="joint_state_controller crane_left_eff_pos_controller" />

    <!-- Loads the controllers -->
    <node name="leftArm_controller_spawner" pkg="controller_manager" type="spawner"
    output="screen" args="$(arg controllers)"/>
</group>
</launch>

I have same namespace into urdf file as well while loading the plugin.

<gazebo> 
    <plugin name="gazebo_ros_control" filename="libgazebo_ros_control.so">
        <robotNamespace>/robot1</robotNamespace>
    </plugin>
</gazebo>

Now whenever I launch the module, I have robot_description param loaded as /robot1/robot_description so controller should be able to find it but that is not the case with me. it gives the following error.

[ERROR] [1646509768.321224385]: Could not find parameter robot_description on parameter server
[ERROR] [1646509768.321700089]: Failed to parse urdf file
[ERROR] [1646509768.321938019]: Failed to initialize the controller
[ERROR] [1646509768.322140682]: Initializing controller 'crane_left_eff_pos_controller' failed
[ERROR] [1646509769.337931]: Failed to load crane_left_eff_pos_controller

Now here comes the best part, Everything runs smoothy when I have robot_description param loaded as /robot_description. On top of that if I do not use effort_controllers/JointGroupPositionController and use effort_controllers/JointPositionController for individual joints, the controller identify the robot_description loaded into namespace /robot1/robot_description

Please let me know if you know some way to solve this. If you want more information on the issue, please let me know.

Thank you.