Command Block problem

I use a world in a realm (Minecraft Bedrock for Playstation 4) and I activated command blocks before the creation of the world. I had been using command blocks successfully until the last update. Now when I write a command in the block (and I close the interface of the block) the command doesn't work: when I re-open the block interface the command was cancelled. I tried to download the world from the realm in order to change an eventual setting error, but the download stopped at 659.00 mb, so I couldn't have a copy of the world.