For whatever reason, they were unable to tap into it, feel or use it, and as a result, they were fascinated by the potential of Force-sensitives like Luke Skywalker.
The Ssi-ruuk, a race of reptilians from outside the main galactic body, were completely separated from, or blind to, the Force.
According to the Legends continuity, there were two races of beings who were specifically said to not be able to use the Force.
