"Attempting to accept the next goal when a new goal is not available"

edit

Hello! I'm trying to perform an action-client/action-server structure using a callback structure.

So it just has to read info from the goal and publish messages on a turtlesim topic.

When I run this node (either before or after I created the client) every time the server receives a Goal I get this:

[ INFO] [1501865084.462187784]: Server Created    
[ INFO] [1501865086.638608252]: I'm in goalCB() and I'm receiving a new Goal
[ERROR] [1501865086.638780375]: Attempting to accept the next goal when a new goal is not available

This is my code (which btw for now does nothing, I just wanted to see if everything worked)

class polygonAction
{
public
:
polygonAction(std::string name) : 
    as(nh_, name, false),
    action_name_(name)
  {

//register the goal and feeback callbacks
as.registerGoalCallback(boost::bind(&polygonAction::goalCB, this));
as.registerPreemptCallback(boost::bind(&polygonAction::preemptCB, this));
ROS_INFO("Server Created");

//Stuff for turtlesim we don't care
[...]

as.start();


}

  ~polygonAction(void)
  {
  }

  void goalCB()
  {
    ROS_INFO("I'm in goalCB() and I'm receiving a new Goal");
    goal_length = as.acceptNewGoal()->length;
    goal_sides = as.acceptNewGoal()->sides;
    ROS_INFO("Received %d sides and %d lenght", goal_sides, goal_length);

  }

  void preemptCB()
  {
    ROS_INFO("%s: Preempted", action_name_.c_str());
    // set the action state to preempted
    as.setPreempted();
  }

  //Stuff for turtlesim we are not interested in 
 [...]

protected:



  ros::NodeHandle nh_;
  actionlib::SimpleActionServer<es_1::polygonAction> as;
  std::string action_name_;
  int goal_sides, goal_length, sides_count;
  es_1::polygonFeedback feedback_;
  es_1::polygonResult result_;
  ros::Publisher pub;
  ros::Subscriber sub;

    };

int main(int argc, char** argv)
{
  ros::init(argc, argv, "polygon_action_server");

  polygonAction polygon("polygon");

  ros::spin();

  return 0;

}

Any ideas?