Each website address is linked to a physical IP address on the web. This is the IP address of the web server from which the website is retrieved to the requested browser window. When Chrome can’t map the website address entered to an IP address then you will see the error “ERR_NAME_NOT_RESOLVED”.
This essentially means the website is down or the domain name system (DNS) in your location could not resolve the site address to an IP. If only particular site is not opening then find the IP address of that site and directly enter the IP address on the browser’s address bar.
If you see the site opens then change your DNS to Google public DNS or approach your internet service provider (ISP) for more details.