Can't unlock bootloader

[saheermirza]

Model: ZS620KL
RAM: 6G
Firmware/APP Version: 8.0
Frequency of Occurrence: 4g
Rooted: No
APP Name: Unlock device tool
Screenshot: https://us.v-cdn.net/6031231/uploads/ww_attachments/201901/08/155054m2uuo23ui0ulull5.jpg

I want to unlock my device bootloader but always gives error

[ServiceE_Asus]

Hi saheermirza, Good day, Could you kindly tell me which firmware version are you currently on? (settings> system > about phone > software information> build number) Please also send me your serial number by PM for a check. (settings> system > about phone > status > serial number) Thank you.

[saheermirza]

V80.30.96.221I want to unlock my bootloader but there is unknown error all the timeSr.no J6AAGF02W134FJE

[ServiceE_Asus]

Hi saheermirza, Good day. Sorry for my late reply. I would suggest you update the firmware to the latest WW-90.10.138.181. And reinstall the Bootloader Version V9.1.0.7 from Asus support page. Unlock Device App: Unlock boot loader(for Andriod P) https://www.asus.com/Phone/ZenFone-5Z-ZS620KL/HelpDesk_Download/ Have a try. Thank you.