The GPU must be turned on in the preferences on for Face Crop to run.
The next thing to check is if Face Detection in Photoshop itself is working.
Please open an image with a clearly visible face. In the Photoshop menu, go to Filter > Liquify. In the face Aware Liquify settings, does it show Face 1 in the dropdown? If so, try to move some of the sliders for smile, eye size, ect. Does this morph the face shape? If the Face Aware liquify works properly then we know face detection in Photoshop is working. However, if this isn’t working then there is an issue with face detection on the Photoshop side.
Let me know and we will proceed from there.