@Camilla73 if that's 'no satellite signal' (not 'no signal') turn your box off at the plug and check that the dish connections at the back are still securely fitted.
If after switching back that hasn't fixed it, the cause is most likely a fault with your dish or cables. 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.
