LG G6 h873 unlock fail

Unlock4samsung Wednesday, October 17, 2018

Hi we have tried a few times to unlock this and get the same error every time.
Please advise:

Chimera Mobile Phone Utility version: 19.01.1305 @ 2018-10-17
Printing phone history

EFS Clear Unlock
17/10/2018
11:54:01
PM

EFS Clear Unlock
Initializing...
IMEI: xxxxxxxxxxxxxxx
Reading modem calibration
Waiting for diag serial port to appear...
Please make sure Port Check Test is enabled on the phone!
Be patient! Do NOT disconnect the phone!
Creating backup file
Creating backup...
Saving Qualcomm files.
629 files saved.
Saving special file.
895 files saved.
Saving nv items.
497 nv items saved.
Waiting for serial port to appear...
Trying to boot the phone into download mode...
Waiting for download mode serial port to appear...
Creating EFS backup...
Waiting for download mode serial port to appear...
Reading EFS partitions. Do not disconnect the phone!
EFS data saved successfully!
Starting Unlock...
Waiting for download mode serial port to appear...
Protocol failure detected
Finished at local time: [10.17.18 16:59:29]
WorkID: 46033741