Galaxy S6 IMEI Null Solution

Any Body Please Help. My S6 G920FD IMEI Null. i try write

efs – Succes
Cert – Not Succes Following Error

" Operation: Write CERT
Selected model: SM-G920F
Software version: 24.3

Waiting ADB device… OK
Reading phone info…
Model: SM-G920F
Android version: 5.1.1
Product code:
Phone version:
PDA version: G920FXXS3COK5
CSC version: G920F3IE3COJ1
CSC country code: Ireland
CSC sales code: 3IE
HW version:
Phone S/N: RF8G4198MCF
Modem board:
RF cal date:
Checking Super user right… true
Initialization AT RIL… error
Done with Samsung Tool PRO v.24.3 "

Can Support to me