Need help for naval training


I need help in torpedo gun-boat training.
I can reach the task where an LS4 boat captures zone “A”. The training window writes that press the left shift button. I press the button, the window says “You can zoom, if the target is very far away.”
Then I zoom to the target LS4 boat, but nothing happens. The LS4 boat is in a light ractangle, but outside the radtangle everything is darker, and that’s all. I can press any button I like, nothing happens.

Please help go through this part of the training!