1: Suggest you check that the HDMI cable is pushed home in the sockets of both the box and TV, 2: Try a different HDMI socket on the TV, 3:Try another HDMI cable 4:Try different combinations of aforementioned. 5: Try viewing on another TV. Failing that it could could be a hardware problem (dry joint) on either box or TV, No.5 should show which piece is defective.