Couldn't Minecraft be created?

Whenever I type in a command block in Minecraft: summon minecraft: falling_block "coordinates" it just says: Object could not be created.

Does anyone know why or what I can do about it?

Either it's a bug or if you have a server you may have to allow NPCs or something similar.

/ summon minecraft: falling_block ~ ~ 5 ~ {BlockState: {Name: "minecraft: block_den_du_willst}, Time: 1}