You might be aware that while unlocking Redmi Note 5 Pro (whyred) you would face a error while binding which would read "86006" and hence this did not allow you to unlock bootloader.
The issue lies in server sync and can be only solved from Xiaomi's side. Translating the Chinese characters would tell that the error translates to "Illegal Parameter" warning.
Upon investigation, it was noted that the Indian Models which were made in China did not face the error whilst the Indian Models which were made in India faced this error. You can check this by checking box of your phone and seeing on front of box and bottom of rear side of box, if you see "Made in India" sticker or mark then you know you can't unlock bootloader as of now.
We have contacted Xiaomi and they will be releasing a fix soon and no eta has been specified.
UPDATE 1: Xiaomi has started to fix. This won't work on Whyred Models but it is starting to work
Take Backup **Data will be Deleted**
Turn on Mi Sync (Settings -> Sync)
Connect Device to Laptop/Desktop.
Open Mi Unlock tool on your Laptop/Desktop (Download)
Open the App, Install Drivers.
Shut down phone, connect to your Laptop/Desktop and restart in Fastboot Mode (Click Volume Down and Power Button)