systemctl enable rng-tools error

[Birdheezy]

When trying to get this to run at boot, i get to running the command "systemctl enable rng-tools" and get this error:
pi@pi:~/categorical-sectional $ systemctl enable rng-tools ==== AUTHENTICATING FOR org.freedesktop.systemd1.manage-unit-files === Authentication is required to manage system service or unit files. Authenticating as: ,,, (pi) Password: ==== AUTHENTICATION COMPLETE === Failed to enable unit: Unit /run/systemd/generator.late/rng-tools-debian.service is transient or generated.
I've tried running at sudo systemctl enable rng-tools and get the same error (Failed to enable unit: Unit /run/systemd/generator.late/rng-tools-debian.service is transient or generated.)

Everything else seems to work just fine.