Hello,
This is a bug report.
The Shadow Generator (is that the English name? Or is it Paradox Device?) Tower of the Allies is sometimes not working in multiplayer games. You know the tower with the spinning fork on top which creates a shadow so the enemy cannot see into your base. Sometimes it does work, sometimes not. And when it does not work, it won't work for the whole duration of the game.
A fix would be greatly appreciated.
Fun fact - Though it doesn't work for me at times, the enemy apparently is able to build working towers in the same game where my own towers don't work.