Dish 811 Lost Digital Feed

[ddny]

A few days my OTA digital channels disappeared - blank screen, dead, nada. Analogs are OK. The 811 program guide shows yellow on each digital channel which I take it indicates lack of signal.
What might have happened? Is it possible just the receiver's decoding section went down? Is Dish getting even with me for dropping programing? Can I troubleshoot this in any way? Thanks for ideas.

[ddny]

Saving anyone the time to post an answer. I got the digital channels back. I still don't know what happened. Solar activity?

[ddny]

Since I cannot acquire the Dish program guide, I am guessing that somehow the receiver is not being enabled. However, it seems to recognize the sattellite when I try the installation routine. Is it possible that with summer some big trees have leafed out to block the signal? There is a lot of foilage in the path to the southwestern sky.