In response to your enquiry, we would like to inform you that the unlock code application service has ended, as of July 25th 2018, to ensure user experience and safety. Moreover, unlocking the bootloader of a device voids the warranty and it wasn’t recommended since it was the source of multiple software issues due to unauthorized software modifications.
(以下ソース)
https://uk.community.huawei.com/software-40/how-can-i-unlock-bootloader-220

要約：Bootloader Unlockサービスは2018年7月25日に終了しております(Huawei公式)