could not connect to server

i have been trying to unlock g930t from yesterday, l have tried more than 10 times, but every time it says could not connect to server


Operation: Unlock
Selected model: SM-G930T
Selected port: COM1 Communications Port
Software version: 32.7

Checking Login and Password... OK
Ballance: 35 crd.
You have 35 credit(s) left. This operation takes 10 credits.Continue? Yes
Waiting ADB device... OK
Reading phone info...
Model: SM-G930T
Android version: 7.0
PDA version: G930TUVS4BQJ2
CSC version: G930TTMB4BQJ2
Phone version: G930TUVS4BQJ2
Product code: SM-G930TZKATMB
CSC country code: USA
CSC sales code: TMB
Phone SN: R58H218NSJY
IMEI: **************
HW version: REV0.6
RF cal date: 2016.02.16
Chip name: MSM8996
Modem board: MSM8996
Security patch: 2017-11-01
Boot Warranty bit: 0
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... COM25 detected
Reading data from phone... OK
Calculating... OK
Searching server... error
could not connect to server

Done with Samsung Tool PRO v.32.7