Double click on tab doesn't give the autocompletion

I am in the unit 9 where I should type :
rostopic pub /ardone_action_server/goal ardrone_as/ArdroneActionGoal
In order to sent the goal topic by hand instead of roslaunching the action-client package that calls the corresponding action-server package that I’ve just launched.
notice: I have already launched the action-server in the first shell and it’s waiting for a goal to receive!
Any explanations why the double tab this time not working? I am pretty sure the command is correct because when I typed I get :

Usage: rostopic pub /topic type [args…]

rostopic: error: Please specify message values

Hi @mouidsakka01 ,

The double tap on TAB will NOT work if one of the arguments are wrong.

I believe in your case, the problem is that the command should be:

rostopic pub /ardone_as/goal ardrone_as/ArdroneActionGoal

and NOT:

rostopic pub /ardone_action_server/goal ardrone_as/ArdroneActionGoal

Hope that fixes your problems. Let me know if this worked for you!