U2311H HDCP compatibility

I am trying unsuccessfully to play a Blu-ray dvd and Cyberlink BD Advisor reports everything OK but fails the monitor - " digital (without HDCP)". My Nvidia GeForce 8400 GS card also reports "this display does not support HDCP". It is connected through DVI-D cable and works perfectly otherwise. In the spec for the monitor indicates compatibility so what could be wrong?