/clone or probably everything

Hi everyone i need your help because i don't think it's just me, me and my friend have a realm and commands are not working correctly when putting them into a command block or sign when i do /clone -788 60 -287 -788 60 -287 -787 61 -287 in a command block i go out and go back in it does ###################### this and i haven't tried with other commands but my friend tested it in another realm and same thing happened i tried on the world that isn't a realm and it works so only realms seem to be having this issue