Limited range of channels when ch+ or ch-
I'm posting this because I had been having this problem for a couple days, and tried several things to fix the problem before finding the solution tonight.
I recently found that when I was hitting the ch+ and ch- button on my remote, I was cycling between channels 250-260, no matter where I started. I tried a different remote, rebooting the set-top box, and neither worked. I found a similar problem in a post here from 2014, the cause of which being a new (at the time) feature.
It turns out that I had set the guide to "Kids Channels" a few weeks ago. The fix was to hit the guide button twice, and then select All Channels (the usual default).