I got the message, “User authentication failed”.

Symptom: When entering the GDS/KDS diagnostic function,

                 you got the “The user authentication failed while executing the relevant function(Code: 4001)”. 

○ Solution1. Relog-in GDS/KDS

1. Log out of GDS/KDS.

2. Close all apps running on the tablet, including GDS/KDS.

3. Run GDS/KDS and log in, then try again.

         If the above method does not resolve the issue,

         follow the Solution2 below:

○ Solution2. Delete the data and cache of the GDS/KDS app.

1. Log out of GDS/KDS.

2. Close all apps running

    on the tablet, including GDS/KDS.

3. Go to the path on tablet PC.

    Path: (Android) Settings -> Apps -> GDS-Smart/GDS M -> Storage

4. Select Clear Data or Clear Cashe to proceed with deletion.

     (All inspection data saved on the tablet will be deleted)

5. Run GDS and log in, then try again.