Error > !_src.empty() in function 'cv::cvtColor'

I am getting the error in the title in this code, how can I solve it? I tried different codes and I get the same error again I am using OpenCv(4.6.0) version

while cam.isOpened():
    ret, image = cam.read()  
    image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)        
    results = hands.process(image)    
    image = cv2.cvtColor(image, cv2.COLOR_RGB2BGR)    
        
    if results.multi_hand_landmarks:
      for hand_landmarks in results.multi_hand_landmarks:
        mp_drawing.draw_landmarks(
            image,
            hand_landmarks,
            mp_hands.HAND_CONNECTIONS,
            mp_drawing_styles.get_default_hand_landmarks_style(),
            mp_drawing_styles.get_default_hand_connections_style()
            )