CGrups2 | Invalid environment block

Hey :), I’m stuck with a problem at my Fedora 32. I’d like to do something with docker, which according to my research is a bad idea already. Nevertheless I found an online “tutorial” on how to get it to work. They recommended sudo grubby --update-kernel=ALL --args="systemd.unified_cgroup_hierarchy=0. But when I execute this command it only tells me several times grub2-editenv: error: invalid environment block Did someone had this problem before me or is able to help in some other way?
Thanks in advance