When yоu аre in Hоnоrlock, open up the cаmerа preview, which you can do by clicking the Webcam button on the blue toolbar at the bottom of the screen. If you see the external webcam is not selected, you can reach out to Honorlock for support so they can get the external camera reconnected. You are accountable and know if the external camera is being used. Have you selected the external camera and opened the camera preview?