Z3x Box Show Always Error In Writing Cert A700f

Hello Dear Blang Sir,

i try to write cert 10 times in 10 diffrence phones in a700f by z3x box

and i always show error

Code:

  BACKUP INSTRUCTIONS:
    Phone must be rooted!
  If the software can't root the phone automatically, 
  then you must root your device manually.
  1. Power on the phone.
  2. Tap 7 times on 'Build number' in 'Settings'-'About phone' to enable 'Developer options',
     go to 'Settings'-'Developer options' and enable 'USB debugging'.
  3. Connect the phone to PC with USB cable, install drivers if needed.
  4. Select device in ADB settings.
  5. Press 'Read EFS' button to read backup or 'Write EFS' to restore.
  6. Press 'Read CERT' button to read certificates or 'Write CERT' to restore.
  7. Press 'Write NV DATA' if you need to restore NV backup. 

Operation: Write CERT
Selected model: SM-A700F
Software version: 25.5

Checking certificate file... error
Incorrect Public key

Done with Samsung Tool PRO v.25.5