My bootloader won't unlock

[Android Central Question]

I have a lenovo vibe x3a40 and i am trying to flash custom recovery in it . So first i have to unlock bootloader. I have adb tools and i connected my phone to pc and i rebooted my phone to bootloader. I typed in "fastboot oem unlock go" to unlock bootloader but cmd says " failed: can not use this command on user version" so i am stuck here. Can anybody help me please?? Thank you

 

[Cj Eva Frass]

the command is "fastboot oem unlock"