Herald of ice not working

I turned on Herald of Ice but it doesn’t activate. The icon doesn’t show up, but it still reserves mana. This has been happening for a while and I can’t get it to work.

https://cdn.discordapp.com/attachments/1245366777286758430/1457113351674138828/IMG_6177.png?ex=695ad20e&is=6959808e&hm=32316372b35e11857a5f493c6ad524e943d7c01bde1b455d92d9bdd5df68815a&