Is your raycast being fired in the correct direction (Use the debug option in the raycast action). If not, it's possible you've not set your "Look at" action correctly in an earlier state. It needs to be Every frame, and have the correct game object set (Target).
If it's being fired in the right direction, but isn't detecting the object, they it could be that you've not set the raycast action to store the hit object, or you've filtered by a layer that your target isn't on, or your target doesn't have a collider attached.