control rig basic IK not working

I am struggling to figure out why I can’t get my controller in control rig to work with my Basic IK chain. I have checked the rig inside of Unreal and it is working fine, but when I go to setup controllers in control rig to use the Basic IK node, I get the error:

item lengths are not provided either set item length or set effector item. It seems like this is an obvious solution, but I can’t figure it out. Any help would be much appreciated!