SM-G930a can't unlock

i tried 2 firmwares the same problem

Checking Login and Password... OK
Ballance: 5 crd.
You have 5 credit(s) left. This operation takes 5 credits.Continue? Yes
Waiting ADB device... OK
Reading phone info...
Model: SAMSUNG-SM-G930A
Android version: 7.0
PDA version: G930AUCS4BQC2
CSC version: G930AATT4BQC2
Phone version: G930AUCS4BQC2
Product code: SM-G930AZDAATT
CSC country code: USA
CSC sales code: ATT
Phone SN: R38H40VA4WV
IMEI: 3555xxxxxxxxxxx
HW version: REV0.6
RF cal date: 2016.04.27
Chip name: MSM8996
Modem board: MSM8996
Security patch: 2017-03-01
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... COM26 detected
Reading data from phone... OK
Calculating... OK
Searching server... OK
Waiting for server answer... error (1)

Done with Samsung Tool PRO v.33.8