For the past several weeks i am unable to view 4K on my setup. Everything formerly worked. The 4K resolution test works as well. NOTHING HAS CHANGED since the original installation. Now when I go to any 4K channel I get the message that I am viewing in 1080p, the highest resolution possible. 4K works fine with the built in TV apps, and with other attached peripherals, but not with DTV. Any ideas what has happened or how to correct the problem?