If you can't activate the Shield of peace, then it's due to one of these reasons:
- Any player who has access to the Royal Treasury can purchase a bonus "No Salvation", which will not allow players within the kingdom to activate the Shield of Peace for 1 hour or 1 day, depending on the level of the bonus purchased.
- If you attack an enemy player while shielded, your Shield of Peace will deactivate and you will not be able to put it on again for 20 minutes. After that, the only way to extend your protection is to activate a new Shield of Peace.
- You have sent reinforcements to an allied city.
- You have reinforcements in your city.
- You have marches launched at enemy players.
- You have points in the "Clash for the Throne" tournament