Shows Set To Record, But Don't

Did anyone have a problem recording Big Brother last night (9/15)? Although my DVR was set to record it and there was a checkmark indicated on my Guide, when it was time for Big Brother, it did not switch to record and of course, it was not in my recorded programs. It did the same thing with Americas Got Talent. I hope it's a Cox system problem, and that I don't need to replace my cable box......again. Of course, I reset all of the boxes, but that did not fix the problem.