Firstly, check if the problem’s happening on more than one channel. If your picture problem only occurs on one channel, the problem’s likely to be with the broadcaster. Wait a few minutes and then try the channel again.
If you're in the UK, you can also check the Service Status page for any network outages in your area that could be causing a problem.
Secondly, bad weather; such as heavy wind, rain, snow, or storms can interfere with your satellite signal. If the weather’s bad where you are, wait for it to return to normal to see if that fixes the problem.
If your viewing is currently impacted, you can use your On Demand and Recordings until the weather has improved.