Trying to install a FT sensor on the GEN3 arm

[MahrukhAzh]

Hello,

As a beginner in ROS, i am trying to implement a FT sensor at the end effector of the GEN 3 ARM. My initial problem is that gazebo does not recognize the 'FT_sensor' joint (error: [FATAL] [1701011286.835621614]: gazebo_ros_ft_sensor plugin error: jointName: FT_sensor does not exist) as it is mounted on fixed joint (see code below).
I tried multiple times to see how the 'FT_sensor'fixed joint could be recognized in the .sdf that gazebo is taking it but no chance.

Here is my code below:

(gen3_macro.xacro description file)

<?xml version="1.0"?>

<robot name="gen3_arm" xmlns:xacro="http://ros.org/wiki/xacro">
(...)

    <link name="${prefix}end_effector_link" />
<joint
  name="${prefix}end_effector"
      type="fixed">
      <origin xyz="0 0 -0.0615250000000001" rpy="3.14159265358979 1.09937075168372E-32 0" />
      <parent
        link="${prefix}bracelet_link" />
  <child
    link="${prefix}end_effector_link" />
      <axis
        xyz="0 0 0" />
    </joint>
    
    
    <link name="FT_sensor_link"/>
    <joint name="FT_sensor" type="fixed">
      <origin xyz="0 0.05639 -0.00305" rpy="3.14159265358979 3.14159265358979 0" />
      <parent link="${prefix}end_effector_link" />
      <child link="FT_sensor_link"/>
    </joint>
      
    <gazebo reference='FT_sensor'>
      <disableFixedJointLumping>true</disableFixedJointLumping>
      <preserveFixedJoint>true</preserveFixedJoint>
    </gazebo>
      
    <gazebo>
      <plugin name="Force_Torque_sensor" filename="libgazebo_ros_ft_sensor.so">
        <updateRate>100.0</updateRate>
        <topicName>ft_sensor_topic</topicName>
        <jointName>FT_sensor</jointName>
      </plugin>
    </gazebo>
    
    <xacro:if value="${vision}">
  <link name="${prefix}camera_link" />
      <joint name="${prefix}camera_module" type="fixed">
    <origin xyz="0 0.05639 -0.00305" rpy="3.14159265358979 3.14159265358979 0" />
    <parent link="${prefix}end_effector_link" />
        <child  link="${prefix}camera_link" />
      </joint>
      
      <link name="${prefix}camera_depth_frame" />
  <joint name="${prefix}depth_module" type="fixed">
        <origin xyz="0.0275 0.066 -0.00305" rpy="3.14159265358979 3.14159265358979 0" />
        <parent link="${prefix}end_effector_link" />
    <child  link="${prefix}camera_depth_frame" />
      </joint>
      
      <link name="${prefix}camera_color_frame" />
  <joint name="${prefix}color_module" type="fixed">
        <origin xyz="0 0.05639 -0.00305" rpy="3.14159265358979 3.14159265358979 0" />
        <parent link="${prefix}end_effector_link" />
    <child  link="${prefix}camera_color_frame" />
      </joint>
    </xacro:if>
    
        
  </xacro:macro>
</robot>

Also, i noticed that the end effector joint does not appear also as joint in the gazebo simulation. Is that normal? Or am I missing an information to activate it? Any help would be welcomed. Thank you for your time!