In ROS2, when a lifecycle node, like the controller_server, creates a publisher, this publisher needs to be activated (in contrast, a publisher doesn't have to be activated if the publisher has been created by a normal rclcpp::Node). A publisher is activated via a simple call to on_activate(). For example,

 some_publisher_->on_activate();

So, if the system is otherwise working and the controller_server lifecycle node has been activated, the message would indicate that the clearing_endpoints publisher hasn't been activated.