Could be some incompatibility problem between cable and laptop. I bought a Lonelec cable but I couldn't get it to connect. After some email exchanges with the cable supplier, he came to the conclusion there was a fault with the cable, so he sent me a replacement cable free of charge. It made no difference. I still couldn't get a connection.
I then bought a cable from Stingerwolf (on this forum) and it worked straight away. Never did figure out why the Lonelec cables wouldn't work with my setup.