Can't proceed further Kharkov 1

[Torques]

I'm at that map where you are asked for the first time to use binnoculars (you go upstairs and are asked by the leader to target the enemy) to spot the enemy. It doesn't work, even the one piece of artillary I can see, no red x comes up or anything. The little box in the bottom right of the screen is empty, how can I go forward thanks.