Wifi not working

[Studale]

My sky broadband Wifi is not working on any device. I have tried unplugging it etc, but still down.
When I check the connection it says all ok?

[MThom1]

Same! Every few minutes it disconnects. 

[Crowby]

Same. Can connect to the router but router won't connect to the internet since this evening. Middle light permanently amber. Powered off and on twice, hasn't sorted it.