Connected to the Internet, says I have access but nothing works

So I am connected to the router via an ethernet cable connected to an extender, which in itself is connected to the router wirelessly. I am using Windows 7, and the network icon is the one showing you're connected, and it also says I have Internet access. I can, however, not connect to Steam, Twitch or any other programs that require Internet to connect, and every page I try to open in Mozilla times out. I can use the Internet on my phone, which is connected to the extender's connection. This is why I can't pinpoint what caused the problem. I tried switching ports, the cable itself, IP resetting command and IP renewal command. Nothing worked. I am out of clues. Any ideas? Also, excuse my English.