Sending loader... Failed [Answered]

Hi guys, there is a problem, I connect the phone board to the computer, the computer finds a new device (you can hear the sound of connecting a new device) (Qualcomm HS-USB QDLoader 9008)
after that i press the button "Connecting"
in the "log" window appears "Connecting ..."
after a couple of seconds "Sending loader ..."
and after another second, the computer again makes the sound of connecting a new device,
and in the "log" window appears "Failed."

I tried two different boards, I tried two different computers, and I even took another Medusa Pro device - and the result is always the same. how can i fix this problem ???
drivers?

Welcome to Medusa Pro Software version 1.6.7.
Started.
Reader #0: Generic EMV Smartcard Reader 0

Model Settings:
Interface : USB
Brand : Samsung
Model : SM-G950U
SRF : C:/Program Files (x86)/Medusa Pro Software/firmwareFolder/SAMSUNG_SM-G950U_USB_UFS.srf
Core : Qualcomm MSM8998 UFS
Loader : QLoader_v3_Samsung

Connecting...
Sending loader... Failed.


Model Settings:
Interface : USB
Brand : LG
Model : H873
SRF : C:/Program Files (x86)/Medusa Pro Software/firmwareFolder/LG_H873_USB_UFS.srf
Core : Qualcomm MSM8996 UFS
Loader : QLoader_v2_LG

Connecting...
Sending loader... Failed.