sm-910f 5.1.1 unlock failed

i try to unlocked this but it failed on unlocking

INFO : 12/20/2015 6:19:10 PM > Platform: Samsung Android
INFO : 12/20/2015 6:19:10 PM > Selected port: COM14
INFO : 12/20/2015 6:19:10 PM > Selected model: SM-N910F
INFO : 12/20/2015 6:19:10 PM > Reading info…
INFO : 12/20/2015 6:19:10 PM > Mode: Normal
INFO : 12/20/2015 6:19:10 PM > Firmware compiled date: Jun 30 2015
INFO : 12/20/2015 6:19:10 PM > Firmware compiled time: 10:00:00
INFO : 12/20/2015 6:19:10 PM > Firmware released date: Nov 9 2015
INFO : 12/20/2015 6:19:10 PM > Firmware released time: 18:33:57
INFO : 12/20/2015 6:19:10 PM > SW Version: MPSS.BO.1.0.r10-00213-M9635TAARANAZM-1
INFO : 12/20/2015 6:19:11 PM > ADB server killed.
INFO : 12/20/2015 6:19:11 PM > Detected phone model: SM-N910F
INFO : 12/20/2015 6:19:11 PM > Firmware compiled date: Wed Nov 11 12:57:26 KST 2015
INFO : 12/20/2015 6:19:12 PM > PDA version: N910FXXS1COK2
INFO : 12/20/2015 6:19:12 PM > CSC version: N910FDRE1COH3
INFO : 12/20/2015 6:19:13 PM > SW version: N910FXXS1COK1
INFO : 12/20/2015 6:19:14 PM > Phone IMEI: Unknown
INFO : 12/20/2015 6:19:15 PM > Phone SN: RF8G30JV5CA
INFO : 12/20/2015 6:19:15 PM > Android version: 5.1.1 (LMY47X)
INFO : 12/20/2015 6:19:15 PM > Checking Root:
INFO : 12/20/2015 6:19:20 PM > Phone is Rooted.
INFO : 12/20/2015 6:19:20 PM > Reading security backup, please wait…
INFO : 12/20/2015 6:19:43 PM > Backup saved as Security-SM-N910F-20-12-2015_18-19-10 file
INFO : 12/20/2015 6:19:43 PM > Unlocking phone…
WARN : 12/20/2015 6:19:44 PM > Phone will restart now. Please don’t disconnect cable!
ERROR : 12/20/2015 6:19:44 PM > Phone unlocking failed
Log file "C:\Program Files\Octoplus\Octoplus_Samsung\LOG-12-2015_16-44-05.log" closed (12/20/2015 6:20:47 PM).

br
shoktong