Error z3x Waiting for server answer... error (1)

Hi need help i have a g950u for unlock but error of server
Checking Login and Password... OK
Ballance: 10 crd.
You have 10 credit(s) left. This operation takes 5 credits.Continue? Yes
Waiting ADB device... OK
Reading phone info...
Model: SM-G950U
Android version: 8.0.0
PDA version: G950USQS3CRE2
CSC version: G950UOYN3CRE2
Phone version: G950USQS3CRE2
Product code: SM-G950UZSACCT
CSC country code: USA
CSC sales code: CCT
Phone SN: R28J636D6WA
IMEI: 3XXX53081212XXX
HW version: REV1.0
RF cal date: 2017.04.15
Chip name: MSM8998
Modem board: MSM8998
Security patch: 2018-05-01
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
Searching Ramdump interface... COM279 detected
Reading data from phone... OK
Calculating... OK
Searching server... OK
Waiting for server answer... error (1)

Done with Samsung Tool PRO v.32.7