You can’t call another blueprint’s event (or function) like that. At the very least you need a reference to an object of the class containing the event.
If it’s the other actor involved in the Overlap, you can use a Cast node to cast OtherActor to the correct class, then pass the result into the event’s Target input.
Otherwise, you’ll need to use the GetAllActorsOfClass node (choose the class containing the “TrackPlayer” event as class type), Get the first element of the returned array and call the event using that.