SM-N910K Writing Certificate failed

octopus team pls help me
my log
INFO : 3/3/2016 4:56:17 PM > Platform: Samsung Android
INFO : 3/3/2016 4:56:17 PM > Selected port: COM5
INFO : 3/3/2016 4:56:17 PM > Selected model: SM-N910K
INFO : 3/3/2016 4:56:18 PM > Selected file: C:\Users\quang anh\Downloads\Cert-SM-N910K_354888060302890.cert
INFO : 3/3/2016 4:56:20 PM > Detected phone model: SM-N910K
INFO : 3/3/2016 4:56:20 PM > Firmware compiled date: Wed Dec 2 14:10:57 KST 2015
INFO : 3/3/2016 4:56:20 PM > PDA version: N910KKTU2COL1
INFO : 3/3/2016 4:56:21 PM > CSC version: N910KKTC2COL1
INFO : 3/3/2016 4:56:21 PM > SW version: N910KKTU0COL1
INFO : 3/3/2016 4:56:23 PM > Phone SN: R39FB0BDR5
INFO : 3/3/2016 4:56:23 PM > Android version: 5.1.1 (LMY47X)
INFO : 3/3/2016 4:56:23 PM > Checking Root:
INFO : 3/3/2016 4:56:24 PM > Phone is Rooted.
INFO : 3/3/2016 4:56:24 PM > Reading security backup, please wait…
WARN : 3/3/2016 4:57:12 PM > Phone will restart now. Please don’t disconnect cable!
WARN : 3/3/2016 4:57:52 PM > Perform the following steps:
WARN : 3/3/2016 4:57:52 PM > 1. Connect phone via UART cable to the Box.
WARN : 3/3/2016 4:57:52 PM > 2. Note: phone screen must be active
INFO : 3/3/2016 4:57:52 PM > Connecting to phone, please wait…
INFO : 3/3/2016 4:57:57 PM > Found phone on COM5
INFO : 3/3/2016 4:57:57 PM > Phone connected successfully
INFO : 3/3/2016 4:57:57 PM > Checking Certificate file…
INFO : 3/3/2016 4:57:57 PM > Certificate file successfully checked
INFO : 3/3/2016 4:57:57 PM > Writing new phone IMEI…
ERROR : 3/3/2016 4:58:14 PM > Writing Certificate failed
INFO : 3/3/2016 4:58:14 PM > Performed by 2.2.1 software version
all model s5,s6,note4 os 5.1.1 Certificate Writing not working