I did what you do. I switched off the box and counted for ten seconds then rebooted. The box came back online but there was still no signal. I had to go to plan B. I googled.
Apparently severe weather can affect the Sky. Ok it's snowing but not that bad. I went to have a look at the dish. The snow was blowing right at it and this wet snowy icy mix had built up on the dish. Right at that moment I knew what was needed. I grabbed a step ladder and a brush and stepped out into the blizzard.
I climbed gingerly to the top of the ladder and swept the snow off the dish.
Success it worked again.
Twenty minutes later the signal was lost.
I switched to terrestrial TV. Too cold out there.