Fail to send a goal to navigate

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Hi, I tried to send the goal to move_base. However, the robot does not move and I get the following error:
[ WARN] : The goal sent to the navfn planner is off the global costmap. Planning will always fail to this goal.

Robot: Turtlebot3 ; OS: Ubuntu16.04 ; navigation package: github

Part of my code sending the goal :

  goal.target_pose.header.frame_id = "/map";
  goal.target_pose.header.stamp = ros::Time::now();
  goal.target_pose.pose.position.x = goal_x;
  goal.target_pose.pose.position.y = goal_y; /*both derived from abs pos. of outlet  in /map or distance wrt to base_link*/ 
  goal.target_pose.pose.orientation.w = 1.0;

The code is mainly from this link. I modified the code according to this problem.

The given map's yaml and pgm file:

image: tunnel_map.pgm
resolution: 0.05
origin: [-10.0, -10.0, 0.0]
negate: 0
occupied_thresh: 0.65
free_thresh: 0.196

https://imgur.com/rqpcdwf This map is like a tunnle where its size is 2m*2m square having an outlet in bottom right.

Turtlebot3 in Rviz: https://imgur.com/Bx0DPLe

Also, I changed frame_id between base_link and /map many times and tried to find the correct coordinate for them, but either the robot didn't move showing the warning mentioned above or plan a path to the center of the grid map whatever the value of position.x and position.y is.

Thank you for taking the time and effort in reading this problem~ and please let me know if anything is unclear.