Ps4 /Fill command not working properly

So I just started using the /fill command on my PS4. It works fine until I go to add hollow, outline or keep after the needed Cords & block choice. The strange part is the game acts as if it wants to accept the command by giving me those options if I add a square bracket after the block choice; but once I hit enter I’m given a syntax error message and I’m not sure what I’ve done wrong. I’ve looked at many YouTube videos & Reddit feeds and other forms to try to figure it out but nothing seems to work. So I’m here, hoping y’all can fix it eventually. Thank you!