I think it's happened to me three times in three years. I now know that this isn't a problem with the equipment in the house, it's something the engineers have to fix somewhere. However, it's impossible to convince the help line that this is the problem. So they insist on booking an engineer. You wait three days fro the engineer, then they turn up an say 'This isn't a problem I can fix, it's a prblem with the server (or something). Then a couple of hours later it works again.