My non-X1 set top box will not longer show HD channels

I have two RNG150N boxes. I have an HD account and usually they both show all available content. One I haven't used for a few months so I had turned off (24 watts when its off btw). When I turned it on yesterday to use this week it would only show SD channels. No wiring or equipment changes have occurred. I tried to reset the box and Xfinity could not contact it. I gave it overnight to try and sort itself out and no joy today. Screen says "ONLY AVAILABLE WITH HD SERVICE". The other RNG150N is working fine. Worst case I could swap the boxes but that is pretty low rent. Did leaving it turned off zombie the box? Thanks.