Installed Steam via flatpak. When using the run command I get:

"bwrap: No permissions to creating new namespace, likely because the kernel does not allow non-privileged user namespaces.
On e.g. debian this can be enabled with 'sysctl kernel.unprivileged_userns_clone=1'."

I've tried using sysctl but the file can't be found. I've seached Google and found different fixes involving sysctl and chmod, but none of them has worked.

Does anyone have a solution for this? I'm running Ubuntu 18.04 on a Chromebox which has a chroot made with crouton.

TIA!