How do you make sure that you’re troops are safe while sleeping during a war

Make shure powerfyl defensive stacks block roadways

Well there are really not any solid ways to ensure they're safe. For example, my two allies betrayed and crushed me in the middle of the night. Your troops being unsafe when you're asleep is a natural part of the game. Almost everyone has had the experience. However, my suggestion to you is that you should always place spies in suspected enemies. This will give you more intel about their actions and messages. Also, don't necessarily place your troops on the border. This will make sure that they don't get destroyed by bombers and artillery. Place powerful weapons like nuclear bombers or rockets deep inside your territory outside enemy reach. To make sure you're completely you can always play as an island nation. Launching an naval invasion is no easy thing, the enemy troops have to take hours to disembark before attacking. This would ideally give you more time to prepare and attack. Furthermore, you can use stealth troops like submarines as an early detection measure.