Bootloop an I can't unlock bootloader via CMD

[nicobelic]

I found a video that shows the SAME PROBLEM I'm having with my Mi A1.
https://www.youtube.com/watch?v=51LnEOrM3nQ

Why can't I fix the problem? I can't unlock the bootloader. I type "fastboot oem unlock" on the CMD and this message appears

Failed "remote: oem unlocked is not allowed"

This shows up when I tried reinstall the ROM via MiFlash: https://imgur.com/uAVuFle

 

[KorokHidup]

I bet you have tried to flash mi 5x rom on your mi A1 before right?

 

[nicobelic]

I bet you have tried to flash mi 5x rom on your mi A1 before right?

Absolutely not. I tried to reinstall the official rom and then this happened.