I have two tivos on one TV - a premiere and an HD. Cable split.
Right now tonight, channel 627 is fine on the HD. But on the premiere says the channel is not authorized. 628 is fine and 626 is fine but not 627. It worked fine yesterday on the Premiere and all the days before that. (627 is my baseball channel.)
What's the deal? It's clearly not a Comcast issue.
This premiere (I've only had it a few months) is really a good news/bad news machine. Initially, I only kept the HD because it's a lifetime machine, but now I'm sure glad I have it. The Premiere is so damn buggy. It makes me crazy.