galaxy s6 g920t ztool error

I have tried everything to repair the IMEI and always gives me error that I can do

Operation: Write CERT
Selected model: SM-G920T
Software version: 24.1

Waiting ADB device… OK
Reading phone info…
Model: SM-G920T
Android version: 5.1.1
Product code:
Phone version: G920TUEU3COK1
PDA version: G920TUEU3COK1
CSC version: G920TXAR3COK1
CSC country code: USA
CSC sales code: XAR
HW version:
Phone S/N:
Modem board: SHANNON333
RF cal date:
Checking Super user right… true
Initialization AT RIL… OK
Checking certificate file… OK
KEY ID: 0346
Check version… OK
Initializating zTool… error (0)

Done with Samsung Tool PRO v.24.1