コマンドプロンプトのメッセージ貼っておきます

>fastboot oem unlock
...
(bootloader) Showing options on Display
(bootloader) Use device keys for selection　→　ここでunlock bootloader選択
(bootloader) erasing userdate,,,
(bootloader) erasing userdate fone
(bootloader) erasing cache,,,
(bootloader) erasing cache done
FAILED (remote: ()
finished. total time: 4.143s