SM-G950W can not unlock Calculating... OK / BUT.. Error could not connec

SM-G950W can not unlock Calculating... OK / BUT.. Error could not connect server
Flash Modem downgrade already.
Here LOG




Operation: Read Codes via Server
Selected model: SM-G950W
Selected port: COM22 SAMSUNG Mobile USB Serial Port
Software version: 34.3

Checking Login and Password... OK
Ballance: 21 crd.
You have 21 credit(s) left. This operation takes 5 credits.Continue? Yes
Waiting ADB device... OK
Reading phone info...
Model: SM-G950W
Android version: 8.0.0
PDA version: G950WVLU5BRG4
CSC version: G950WOYA5BRG4
Phone version: G950USQU5CRF1
Product code: SM-G950WZKARWC
CSC country code: Canada
CSC sales code: RWC
Phone SN: R28J328Y28X
IMEI: 355757080211770
HW version: REV1.0
RF cal date: 2017.03.20
Chip name: MSM8998
Modem board: MSM8998
Security patch: 2018-08-01
Boot Warranty bit: 0
SIM State: ABSENT
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... COM12 detected
Reading data from phone... OK
Calculating... OK
Searching server... error
could not connect to server
Done with Samsung Tool PRO v.34.3


Try to unlock 3days could not connect to server

Internet hi-speed ok 30MB/s