1. Equipment failure: The failure of the face brushing equipment may result in the inability to brush the face. You can contact relevant maintenance personnel for inspection and maintenance.

2. Unstable network: If the network connection is unstable, there may be a problem with the face brushing device. It is recommended to check the network connection.

3. Low quality of face collection: If the quality of face collection is low, brush face recognition may also fail. It is suggested to re-collect clear facial photos.

4. Unbound or Unbound Account: If the face-brushing system needs to be bound with a user account before it can be used, but your account is not bound or has no permission to enable it, it will also lead to the inability to brush your face.