Kicking me out of game

I don't know why this is but Minecraft recently started to crash and kick me out of the Minecraft app when I try the /fill command. Exp: I would be in my world I Would try to use the fill command to fill a area of blocks to curve into a mountain, so I start typing the fill command the moment I start the put the last coordinates into the command the game would go black screen and it would kick me out of the game so I have to reload my game and try typing it out again and it always kicks me out of the game. And it's getting really frustrating so I letting you know just wondering if there is anything I can do to fix it or I'm not able to use the /fill command?