If you are running into a lot of “Page Not Found” errors and you know you’re connected to the internet, try flushing your DNS cache to have your computer request new information.
Open the command prompt and type ipconfig /flushdns and press key Enter.
Because most computers that are connected to the internet automatically cache the hostname of the websites you have visited to make reloading the pages faster than if there was no cache.
If you used Linux OS then just use this: service restart network-manager and press key Enter. This will flush your fucking DNS.