G935A unlock error

Operation: Read Codes via Server
Selected model: SM-G935A
Software version: 32.4

Checking Login and Password... OK
Ballance: 35 crd.
You have 35 credit(s) left. This operation takes 5 credits.Continue? Yes
Waiting ADB device... OK
Reading phone info...
Model: SAMSUNG-SM-G935A
Android version: 7.0
PDA version: G935AUCS4BQC2
CSC version: G935AATT4BQC2
Phone version: G935AUCS4BQC2
Product code: SM-G935AZSAATT
CSC country code: USA
CSC sales code: ATT
Phone SN: R38H30J4M3H
IMEI: 358445070652461
HW version: REV0.7
RF cal date: 2016.03.12
Chip name: MSM8996
Modem board: MSM8996
Security patch: 2017-03-01
Boot Warranty bit: 0
Rebooting phone... OK
Waiting ADB device... OK
Rebooting phone... OK
Waiting ADB device... OK
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... COM31 detected
Reading data from phone... error (0 1)
Done with Samsung Tool PRO v.32.4