When installing or updating NoMachine on Fedora 31 the following occurs:

SELinux is preventing systemd from 'ioctl' accesses on the file /usr/lib/systemd/system/nxserver.service.

As a temporary workaround, you can add a local policy to SELinux to allow access to that file.

On Fedora 33 warning may look like the following.

 Dec 21 14:36:56 localhost audit[1]: AVC avc: denied { ioctl } for pid=1 comm="systemd" path="/usr/lib/systemd/system/nxserver.service" dev="sda2" ino=444080 ioctlcmd=0x5401 scontext=system_u:system_r:init_t:s0 tcontext=unconfined_u:object_r:nx_unit_file_t:s0 tclass=file permissive=0