Couldn't Verify Device. Can't Get Info, Connect Again

[Regnarp]

I try to unlock my redmi 3 pro with mi flashunlock.
i have enabled oem unlock, usb debugging and fastboot mode in developer options.
i booted my phone in fastbootmode.
i have permission to unlock and when i connect my phone to the pc miflashunlock recognizes a mi device
next i press unlock and after a countdown it says:

Couldn't verify device. can't get info, connect again

and gives me the option to try again.

Can anyone help me?
What am i doing wrong?

 

[torrex69]

what rom do u use? It help very much if u have a developer rom. My phone had a Miui 7 vendor rom (stable) and it didnt unlock tje bootloader. Flashed a developer rom via miflash in downloadmode after that it unlocked without no problem.
Very important that u login with the same acount in the phone and on the unlock tool.