Keep getting message that I cannot access blocks when using commands

I was working on my world in my realm. I was hovering over a section in which I wanted to place some blocks using the fill command. The command used was "/fill -965 100 -10 -803 115 49 stone 1". When I input the command, I received a message stating, "Cannot access block outside of this world". Also, as I earlier tried to clone a section to another section very nearby, I got the same message.