Where does this error generate from? The reasons are various, for example, DNS address is blocked, cookies are expired or wrong, Firewall or antivirus is blocking your connection, you have changed proxy settings in your browser, etc. Once the error appears on your screen, you are not able to access the website but only reload this page by clicking the given option.
Besides this one, you may be bothered by ERR_CACHE_MISS, ERR_TOO_MANY_REDIRECTS, etc. Tip: Internet connections issues are various when using Google Chrome.