please help to unlock LS992ZVF !!

hellow guys ,

any help to unlock LG LS992ZVF
i tried with Z3X and this was the Log :

Phone mode is NORMAL
Switch to DOWNLOAD mode
Phone detected!
Start new sprint unlock...
Laf Protocol: 01000004
Model name: LGLS992
Software verion: LS992ZVF
Android verion: 7.0
Target operator: SPR
Target country: US
Chipset: msm8996
IMEI: 355602074467485
Init EXT4 /system ... done
Detecting sprint type ...
Laf flash error: phone is not supported.
Elapsed: 61 secs. --> (v9.51)