it shows “Mode not supported”. And device’s warranty is out exactly one month ago! Well done WD, well done…
If your TV is saying “Mode not supported,” then HDMI *is* working; it’s just set to a mode your TV doesn’t support.
Have you tried reseting the box back to defaults?
I would try another HDMI cable. They are not all equal. My gold plated super duper cost a fortune one (I didnt buy it, a present!) gave me problems for weeks, “it couldnt be the HDMI cable could it? as its one of the best!” I changed it for another (cheaper) and problems went away.