This NT Add-On will only close all trades and send you an alert when a target is reached, it cannot stop new trades from opening, instead, it will close all your open trades and if you have an automated system running, these trades will continue to open, you can set the alarm to turn off as soon as the target is reached so that it is no longer active, so it will not close new trades opening.
My advice is to add code to your trading system to stop opening new trades when the target is reached.