Make sure you use a USB 3.0 port, which is needed for the scanner to work.
Please note that some users have problems with USB hubs and you cannot expect the scanner to work with a USB hub unless it is powered.
Verify cables and USB connections and try again.
If it continues please reboot your computer and resume.
Sometimes, it has been a problem with the CH340 driver. The file from the appropriate link below should help with it.
Verify the hardware meets requirements. Additional technical information might be found here: FAST FACTS
Still experience problems? Then we are happy to help - contact our support here.