Mode Not Supported. Resolution Not Supported on TV

You didn’t mention whether this is the first HDMI display you’ve ever tried on the WDTV.  If it is, this maybe a long shot but I ran into something like this when I first got my WDTV Live.   The HDMI socket of the WDTV is recessed into the plastic case and I found that it prevented the HDMI cable from seating fully into the receptacle.  It behaved intermittently and sometimes indicated that the display was not supported even though the TV detected that something was plugged in.  I ended up trimming off about 1/8-inch off the plastic that surrounds the metal plug sleeve at the end of the HDMI cable.  Once I did that, the cable seated fully into the socket and I never had the problem since (over 2 years of use now).