Cannot Upload Leonardo ETH

Hi all,

I purchased the item one week ago and while I was normally uploading the code and all of them were working normally, the upload was slow and the message was displayed at the end:

''Connecting to programmer: .avrdude: butterfly_recv(): programmer is not responding''

I tried RESET but with no result.

plz HELP!

Also change usb cable, change pc, change port but still not working!