IK does not turn on in Metahuman control rig

Hello everyone! Can you tell me why I can’t turn on IK?

I turn on the IK of my metahuman rig jumping to the “Animation Mode” tab, then in the “Anim Outliner” select the IK switch you want and check the box of that IK switch under the “Anim Details” tab.

I added two images showing the process, hope they helps.