SM-N950U unlock error

Operation: Unlock
Selected model: SM-N950U
Selected port: COM522 SAMSUNG Mobile USB Serial Port
Software version: 30.8

Checking Login and Password... OK
Ballance: 15 crd.
You have 15 credit(s) left. This operation takes 10 credits.Continue? Yes
Waiting ADB device... OK
Reading phone info...
Model: SM-N950U
Android version: 7.1.1
Product code: SM-N950UZKATMB
Phone version: N950USQU1AQI5
PDA version: N950USQU1AQI5
CSC version: N950UOYN1AQI5
CSC country code: USA
CSC sales code: TMB
HW version: REV1.0
Phone SN: R28J939DHBT
Chip name: MSM8998
Modem board: MSM8998
Security patch: 2017-08-01
RF cal date: 2017.09.23
IMEI: 358505082951241
Waiting for device to become ready... OK
Initialization zTool... OK
Running zTool, please wait...
Start... OK
Initialization... OK
Generate and check client proof... OK
Verify proof by client... OK
Reading data from phone... OK
Rebooting to upload... OK
Searching Ramdump interface... COM27 detected
Reading data from phone... error (3.418)

Done with Samsung Tool PRO v.30.8