Sm-g925i sn none ????

i have sm-g925i 5.1.1

imei is oky but
sn none

any one have edia about
Platform: Samsung Android
Selected port: COM64
Selected model: SM-G925I
Searching for a phone. Please wait…
Please, press "OK" button on the phone to allow USB debugging..
Phone found.
Firmware compiled date: Tue Jul 28 20:07:09 KST 2015
PDA version: G925IDVU2COGA
CSC version: G925IKSA2COGA
SW version: G925IDVU2COGA
Phone IMEI: Unknown
Phone SN: 00000000000
Android version: 5.1.1 (LMY47X)