Hello, Mi Fans!
We released the latest Mi Unlock Tool (V2.2.406.5) a few months back. We have one important announcement regarding the unlock tool, please note that the support for all the older versions of Mi Unlock Tools will be discontinued in the near future in order to concentrate more on the improvement of user experience and the overall process of unlocking bootloaders.
If you face network error or not able to log in the older version of Mi Unlock Tool, please download the latest one from here or download it from here:
[Guide] Important Announcement About Mi Unlock Tool Update!