Ipconfig /flushdns – flushing your DNS cache

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 the IP address of a website changes before your cache updates, you may not be able to load the webpage. 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.

http://www.wikihow.com/Flush-DNS

https://www.whatsmydns.net/flush-dns.html