That suggests you have no signal on one of the two cables from your dish.
You could try turning the box off at the plug and then checking that the two dish connections at the back are still securely connected. Leave it for 5 minutes before switching back on. If that doesn't resolve it, you'll need an engineer to investigate.
Unfortunately Sky no longer provide engineer support for Sky+ equipment unless you have Sky Protect, so you'll need to contact a local satellite engineer to take a look.
Alternatively now might be a good time to consider upgrading to Sky Q. Any dish or cabling issues will be addressed as part of the Sky Q installation at no additional cost to you.
