I'm getting frequent error messages: This site can't be reached. Server DNS address cant' be found.  (Very common sites likewww.eventbrite.com or http://www.att.net%20/

 

It says "try checking the proxy, firewall and dns configuration"

Running windows network diagnostic

Retry

 

Sometimes the second try works, sometimes not..   I tried calling my DSL isp provider. They checked it out. The speed is fine 6.0 but did not have any solution.  I tried powering down the modem and computer and unplugging. but the problem persists. 

 

Any thoughts for non techie?  No hardware was added or removed in t he home.