Controller Spawner couldn't find the expected controller_manager ROS interface.

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@pregnantghettoteen Maybe naive, but have you installed in your machine the controllers packages you are using?

@Weasfas yes I have done sudo apt-get install ros-noetic-joint-state-controller in the terminal as well as sudo apt-get install ros-noetic-position-controllers and sudo apt-get install ros-noetic-effort-controllers but to no avail. I read in another forum to killall gservers but not sure how to do that.

@pregnantghettoteen, when you launch Gazebo with GUI enabled it can happen that the gzserver is not properly killed. You can kill any process in your machine with kill PID -9 being the PID a number that you can find with the command ps -aux | grep gz. If that is not the case, when the controllers are not able to load is because too much time has passed since the start or the interface you are loading is not compatible with the controllers you are using. One more reason is that the ROS controller manager is unable to find properly the controllers becuase they are not loaded in the proper namespace. Besides, the package you are using refers to a tutorial, have you change anything of that package?

fixed, I did not have the gazebo simulator running

@PGTKing could you please elaborate more. Even I am facing same problem but nothing seems to be working.