Fastboot stucks on three dots

[gogita kupatadze1]

Hello.
I have a problem while unlocking bootloader on my htc desire 310 single sim
It was dead but I recovered it.
Now I want unlock bootloader but on the any command like this
Fastboot oem writes three dots "..." And stucks on it.
Here are steps what I doing.
1.connect to pc
2.enable usb debugging
3.run cmd
4.adb devices(device is showing)
5.type adb reboot bootloader
6.type fastboot devices(device is showing)
7.type fastboot oem device-info and it stucks.

What can I do?
Help me please