Hi there and welcome
It is very possible there was an outage local to your area, do you still have the issue?
Please remove the power to the Sky box and wait 10 minutes
Connect the power to it and tell me if you now get a signal please
ok, then can you check the antenna please as this then would be the most likely cause.
Check the cabling that is going from the main switch to the Antenna for any damage, also the Antenna itself.
Let me know the results please.