If you have followed the steps properly, it should have worked. Make sure to have proper darkness in those platforms. Make it in the ocean maintaining a distance of at least 130 blocks from any land. If it still doesn't work, set your game mode to peaceful and then hard. Wait in the afk room for several minutes. I hope it will work.
![NEW 1.21 CREEPER FARM For Minecraft Bedrock [Mcpe/Xbox/Ps/Ns/windows10]](http://i.ytimg.com/vi/ouSSrKpC__s/mqdefault.jpg)
Not working
If you have followed the steps properly, it should have worked. Make sure to have proper darkness in those platforms. Make it in the ocean maintaining a distance of at least 130 blocks from any land. If it still doesn't work, set your game mode to peaceful and then hard. Wait in the afk room for several minutes. I hope it will work.
Make sure you light the top roof with torches
They don't wanna spawn that much and don't move or fall down