Internt light is off, but I can still connect and use the internet??

Recently bought this router, had it connected to our ethernet port and have been using it for the last few days without an issue unitl just now. Some of our devices do connect to it and some won't, the only common thing about being Samsunt devices do NOT connect, but others will. An odd thing we noticed is that on the lights for the router, most of them are on and working, but the light for the internet is off, no light what so ever. According to the manual it should mean we don't have any internet...and yet I literally am making this post using my router. So we are completely lost on what any of this means, so any advise would be apprciated.