How to fix server not found|Firefox can't find the server error in mozilla firefox

How to fix server not found|Firefox can't find the server error in mozilla firefox-Server not found this method is working in windows 7,windows 8,windows 8.1,windows 10 also.

i m getting error during surfing the internet on firefox..
Server not found

Firefox can't find the server at www.google.com.

Check the address for typing errors such as ww.example.com instead of www.example.com
If you are unable to load any pages, check your computer's network connection.
If your computer or network is protected by a firewall or proxy, make sure that Firefox Developer Edition is permitted to access the Web.